受賞区分：国内学会・会議・シンポジウム等の賞 

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1088/1361-6528/ac6c97

Web of Science

PubMed

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Plasma Processes and Polymers  

Flake-shaped carbon nanomaterials with nitrogen (N) and iron (Fe) addition, so-called carbon nanoflakes (CNFLs), were synthesized by the in-liquid plasma using two different kinds of additive agents, such as hemin and iron (II) phthalocyanine (FePc). According to scanning electron microscopy images and Raman spectra, CNFLs with a size of at least 100 nm order were formed regardless of types of additive agents, and crystallinity of six-membered ring structures was improved as additive agents increased. Photoelectron spectra showed that pyridinic N contents increased from 1.05% to 2.02% with increasing FePc, while those decreased from 0.34% to 0.14% with hemin. In the oxygen reduction reaction, onset potential values also increased from 0.71 to 0.79 eV with increasing FePc, while those decreased from 0.60 to 0.47 eV with hemin. These results suggested that the catalytic activity of CNFLs was effectively improved by the increase of pyridinic N by the in-liquid plasma synthesis with FePc. In contrast, the electron transfer numbers reached 3.81 when hemin increased, although those were less than 2.88 in the cases using FePc. These results mean that the in-liquid plasma synthesis method of CNFLs using FePc has the potential to further improve its catalytic activity.

DOI： 10.1002/ppap.202100203

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Scopus

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Carbon  

DOI： 10.1016/j.carbon.2020.07.052

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Scopus

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Applied Surface Science  

DOI： 10.1016/j.apsusc.2020.146533

Scopus

担当区分：筆頭著者,　責任著者   掲載種別：研究論文（学術雑誌）  

Web of Science

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Sensors and Actuators, A: Physical  

Highly extensible transparent composite materials comprised of maze-like vertically aligned carbon nanowalls embedded perpendicularly into a polyurethane film were used as strain tensors and tested by an electrical resistance method in the course of extension, extension/relaxation and compression/expansion cycles. The maze-like carbon nanowall networks with wall-to-wall average distances of 100, 200 and 300 nm were formed on SiO2-coated Si substrates by a plasma-enhanced chemical vapor deposition system. Afterwards, the nanowall network was embedded into a stretchable polyurethane matrix which enabled a high deformation of the composite. The measured extensibility of the composite was over 440 %, and its resistance increased with the extension. The sensitivity of the detection of extension, which was evaluated by the gauge factor, increased over 2000. These sensor properties can be readily tuned by varying distances of nanowalls within the network. Finally, thanks to their optical transparency in the visible light region and thermoelectric properties, these composites offer a wide range of further practical applications.

DOI： 10.1016/j.sna.2020.111946

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Scopus

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Nano-Micro Letters  

DOI： 10.1007/s40820-020-0395-5

Scopus

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：The Japan Society of Applied Physics  

DOI： 10.11470/jsapmeeting.2019.1.0_1630

CiNii Research

担当区分：筆頭著者,　責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：日本ソノケミストリー学会  

DOI： 10.20577/pamjss.27.0_27

CiNii Research

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：The Japan Society of Applied Physics  

DOI： 10.11470/jsapmeeting.2018.2.0_1777

CiNii Research

担当区分：筆頭著者,　責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：公益社団法人 応用物理学会  

DOI： 10.11470/jsapmeeting.2017.2.0_1758

CiNii Research

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

The InN films were deposited on GaN surfaces at a low temperature of 200 °C by radical-enhanced metal organic chemical vapor deposition (REMOCVD). The REMOCVD system can provide N radicals from the plasma of a N2-H2 mixture gas without using ammonia. Two types of GaN substrate, bulk GaN and GaN on Si(111), were used. The growth mode was modeled as a step flow on the basis of surface morphology observation by atomic force microscopy.

DOI： 10.7567/JJAP.56.06HE08

Web of Science

Scopus

担当区分：筆頭著者,　責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：公益社団法人 応用物理学会  

DOI： 10.11470/jsapmeeting.2017.1.0_1801

CiNii Research

担当区分：筆頭著者,　責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

Deep ultraviolet (UV) photons emitted from Cl2 plasmas become a critical cause of degradation in both photoluminescence (PL) properties and surface stoichiometry as a result of plasma-induced damage on GaN films in Cl2 plasma etching at high temperatures. The damages were formed thermally by photon-irradiations of plasma UV emissions with wavelengths of >258-306 nm from Cl2 plasma at temperatures greater than 500 °C. The damage were observed with a depth of approximately 3.2 nm. The PL property degraded by the UV emission-induced damage at an early period of plasma etching and reached a constant value.

DOI： 10.7567/JJAP.56.096501

Scopus

担当区分：筆頭著者,　責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Clinical Plasma Medicine  

Cancer treatment using non-thermal atmospheric pressure plasma is a brand new and challenging approach for cancer therapy. Conventional cancer therapies are surgery, radio-therapy, and chemo-therapy. We propose plasma-therapy as the fourth cancer therapy. Plasma cancer therapy involves direct plasma treatment of cancers including melanomas, head and neck cancer, pancreatic cancer and liver metastasis, and indirect plasma treatment of cancers by using plasma irradiated solutions such as plasma-activated medium (PAM).We have been recently studying plasma cancer therapy using target cancers such as ovarian cancers, brain tumors, gastric cancers and skin cancers. We have developed a plasma source with ultrahigh electron density, which we have applied to these cancer cells. In addition, we found that plasma-irradiated medium itself can kill these cancer cells. This medium was termed plasma-activated medium (PAM). In vitro and in vivo studies have suggested that PAM is an important tool for cancer therapy especially for disseminated cancers that are currently untreatable.Although many dramatic therapeutic effects of plasma therapy on cancer cells have been reported, the molecular mechanisms of the anti-tumor effects of plasma remain to be elucidated. The greatest challenge for plasma medical science is to understand the complex system that mediates plasma inputs resulting in physiological outputs such as cell death of cancer cells and proliferation of normal cells. Intracellular molecular mechanisms of PAM are also being intensively studied in order to understand the mode of action of PAM. In this review, we summarize the latest understanding of plasma cancer treatments.

DOI： 10.1016/j.cpme.2015.09.001

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Scopus

担当区分：筆頭著者,　責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEEE 2014 Biomedical Circuits and Systems Conference, BioCAS 2014 - Proceedings  

High-sensitivity rapid direct bacteria counting is an essential key method for point-of-care testing. Counting pathogens (cells, viruses, and bacteria) directly in real time with high sensitivity is useful in maintaining human health and preventing pandemics or bioterrorism. However, conventional counting methods with high sensitivity such as the polymerase chain reaction and cultivation-based biochemical testing are time consuming and require controlled places and well-trained staff. On the other hand, conventional rapid approaches such as immuno-chromatography and ATP bioluminescence schemes are insufficient with respect to sensitivity. As an alternative, electro-chemical sensing approaches using a microelectrode have been intensely investigated because of its high-sensitivity, simplicity, and high-throughput. In this work, a CMOS sensor platform with a bacteria-sized (1.2 μm × 2.05 μm) Au electroless-plated 1024 × 1024 microelectrode array for high-sensitivity rapid direct bacteria counting is demonstrated. For high-sensitivity direct pathogen counting, Au microelectrodes are required to be as small as the target cell. By improving a self-aligned electroless plating technique, the size of microelectrodes on a CMOS sensor chip was successfully reduced to 1.2 μm × 2.05 μm, corresponding to 1/20th of the smallest size reported in literature. Two test chips with 1024 × 1024 and 32 × 32 sensor arrays were fabricated in a 0.6-μm CMOS process and microelectrodes were formed on them using electroless plating. In this demonstration, 2D counting used 32 × 32 sensor arrays with silicone (fig. 1) by CV is introduced.

DOI： 10.1109/BioCAS.2014.6981688

Scopus

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

Real time vacuum ultraviolet absorption spectroscopic (VUVAS) measurements revealed that temporal changes in absolute atom densities in H2 and N2 mixture gas (H2/N2) plasmas were affected by the conditions of the reactor inner wall-surface made of anodically-oxidized aluminum. Depending on preceding processes prior to the H2/N 2 plasma process, N and H atom densities decreased for a nitrided wall surface, while no change occurred for a hydrogenated surface. Thus, the process history was revealed in the loss-properties of atoms on the reactor wall-surfaces. Suppressing the temporal variations in the gas-phase atom density is crucially important for realizing the precise control of the material processing with a high reproducibility. © 2014 The Japan Society of Applied Physics.

DOI： 10.7567/JJAP.53.050301

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Scopus

担当区分：筆頭著者,　責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：一般社団法人 日本機械学会  

Although plasma-assisted molecular beam epitaxy(PA-MBE) is a promising technique for GaN growth,the growth rate obtained by this technique is lower than that obtained by metal organic vapor phase epitaxy(MOVPE).In order to improve the growth rate of the technique,high density radical source(HDRS) was developed.By vacuum ultraviolet absorption spectroscopy(VUVAS) measurement,two orders of magnitude higher radical density was confirmed in a comparison of the HDRS and a conventional radical source(CRS).While faster growth rate of 1.4μm/h in GaN homoepitaxy was achieved,better crystalline quality of InxGa_<(1-x)>N(x=0.03〜0.16) epilayers with approximately 1.4μm thickness were also achieved by introducing the HDRS in PA-MBE.

DOI： 10.1299/jsmeiip.2013.5

CiNii Research

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Sensors and Actuators, A: Physical  

Silicon-on-insulator (SOI) wafers made by direct wafer bonding are widely used as starting substrates for microelectromechanical systems (MEMS) fabrication. Adding another layer next to the SiO2 SOI, or replacing it with another material, will be a way to tailor the SOI wafers further. Atomic layer deposition (ALD) can be used to deposit pinhole-free nanometer-thin conformal and smooth inorganic films at low temperatures, making it of interest for many applications in MEMS. In this work, the direct wafer bonding of ALD TiO2, and Al2O3 for reference, is investigated, eventually in order to fabricate SOI wafers with buried ALD oxides. Finding suitable process conditions for TiO2 bonding was challenging: bonding could not be made for TiO2 deposited directly on SiO2 or Si, and annealing at 1100°C gave non-continuous Ti-containing layers. Using a 2-nm Al2O3 under-layer and annealing at 700°C gave void-free bonding with continuous TiO2 and a bond strength of approximately 1600 mJ/m2, enabling the fabrication of SOI wafers with buried TiO2. © 2012 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.sna.2012.05.006

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Scopus

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

In the recovery of photoluminescence intensities for band-edge emissions at around 3.47 eV in the case of gallium nitride (GaN), we have studied the individual roles of hydrogen atoms (H) and hydrogen ions (Hn+). Surface defects such as nitrogen vacancies created by plasma etching were passivated by H termination. By utilizing hydrogen plasmas, we clarified the recovery efficiency by optical and stoichiometrical improvements with respect to the balance between the fluxes of H and H n+. By deflecting H n+ by applying an electric field, the efficiency was improved using an identical H dosage, since the simultaneous irradiation of the energetic Hn+ promoted the desorption of the formed passivated Ga-H bonds. © 2012 The Japan Society of Applied Physics.

DOI： 10.1143/JJAP.51.111002

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Scopus

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Applied Physics Letters  

Two independent ovarian cancer cell lines and fibroblast controls were treated with nonequilibrium atmospheric pressure plasma (NEAPP). Most ovarian cancer cells were detached from the culture dish by continuous plasma treatment to a single spot on the dish. Next, the plasma source was applied over the whole dish using a robot arm. In vitro cell proliferation assays showed that plasma treatments significantly decreased proliferation rates of ovarian cancer cells compared to fibroblast cells. Flow cytometry and western blot analysis showed that plasma treatment of ovarian cancer cells induced apoptosis. NEAPP could be a promising tool for therapy for ovarian cancers. © 2012 American Institute of Physics.

DOI： 10.1063/1.3694928

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Scopus

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Applied Physics Express  

Ultrahigh-speed synthesis of high-crystallinity nanographene was realized using an alcohol in-liquid plasma, which was generated from a nonequilibrium microhollow atmospheric-pressure plasma with an ultrahigh electron density. The synthesis rates of carbon materials were 0.61 and 1.72 mg/min using ethanol and butanol, respectively. Multilayer nanographene structures obtained using ethanol had an interlayer spacing of 0.33 nm, corresponding to that of (002) planes in graphite. The G-, D-, D'-, and 2D-band peaks in the Raman spectrum also confirmed the formation of nanographene. The mechanism of gradual growth of six-membered ring structures was clarified by gas chromatography of the filtrate. © 2012 The Japan Society of Applied Physics.

DOI： 10.1143/APEX.5.035101

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Scopus

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Physics D: Applied Physics  

Superpositioning of negative dc bias in dual-frequency capacitively coupled plasmas (dc-superposed (DS)-CCP) was realized for the selective etching of carbon-doped silicon oxide (SiOCH) films over carbon-doped amorphous silicon (SiC) films, while the dc bias exceeded about 800V. When a dc bias of 1200V was superposed on 60MHz VHF power on the top electrode opposed to a wafer on the bottom electrode biased with 13.56MHz power, a selectivity of above 50 for SiOCH over SiC was obtained. From characterization of the plasma density and various chemical species in the gaseous phase, such as CF 2, CF and atomic N, the density of CF 2 significantly decreased with the application of dc bias ranging from 800 to 1200V. This indicated that CF 2 radicals were consumed at the surface of the counter electrode which was made of silicon. The bulk densities of the species including CF 2 were decreased, especially due to excess surface loss caused by the bombardment of highly energetic ions accelerated by the superposed dc bias, as well as the rf sheath for the superposition of the negative dc bias. The DS-CCP technology is thus concluded to be indispensable for yielding highly selective etching of SiOCH over SiC.

DOI： 10.1088/0022-3727/45/2/025203

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Scopus

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

Super hydrophobic and super hydrophilic surface treatment methods for carbon nanowalls (CNWs) which are carbon nanostructures consisting of stacks of graphene sheets vertically standing on substrates and having ultra high aspect ratios of over 50, were developed using atmospheric pressure plasma, and their mechanisms were discussed on the basis of the elemental compositions of surfaces. The contact angle of water droplet on CNWs markedly decreased from 137.3 to 6.2 with the atmospheric pressure plasma treatments using Ar gas. This indicates the super hydrophobic and super hydrophilic transition of CNW surfaces. Although a morphological change was hardly found, the surface compositions of fluorine and oxygen atoms markedly changed after the plasma treatment for only 5 s. Furthermore, the treatment time dependence of the surface tension of CNWs indicates two different mechanisms at earlier and later stages of surface modification using atmospheric pressure plasma. © 2012 The Japan Society of Applied Physics.

DOI： 10.1143/JJAP.51.01AJ07

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Scopus

担当区分：筆頭著者,　責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Proceedings of the 16th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2012  

We developed carbon nanowalls devices (CNWs), on which graphenes vertically stand in the nanometer spacing like "graphene forest", with different wettability. CNWs permitted cell adhesion and proliferation, and especially super hydrophobic CNWs enabled easy and less invasive cell collection. Furthermore, collagen coated CNWs successfully enhanced the differential ability of the human mesenchymal stem cells (hMSC) to osteoblast cells compared to collagen coated polystyrene culture dishes. Thus, CNWs have superior many properties as cells scaffolds and are expected to be useful for regenerative medicine.

Scopus

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

Photoresists used in advanced ArF-excimer laser lithography are not tolerant enough for plasma etching processes. Degradation of photoresists during etching processes might cause not only low selectivity, but also line edge roughness (LER) on the sidewalls of etched patterns. For a highly accurate processing, it is necessary to understand the mechanisms of etching photoresists and to construct a new plasma chemistry that realizes a nano scale precise pattern definition. In this study, the modified layers formed on the surface of a photoresist by the bombardment of fluorocarbon ions of CF+, CF 2+, and CF3+, and argon (Ar) ions were analyzed by X-ray photoelectron spectroscopy (XPS). The etching yield of the modified steady-state surface was almost dependent on the mass of incident ion species. The surface composition was modified with increasing dosage of each ion species, and reached a specific steady state that was dependent on the ion species. The bombardment of F-rich ion species such as CF2+ and CF3+ resulted in the formation of not only fluorocarbon layers, but also graphite like structures on the surface. On the basis of these results, the surface reaction for the ion-beam-induced modification was discussed. © 2011 The Japan Society of Applied Physics.

DOI： 10.1143/JJAP.50.08JE05

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Scopus

CiNii Books

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Solid-State Electronics  

We have demonstrated the control of interfacial properties of Pr-oxide/Ge gate stack structure by the introduction of nitrogen. From C-V characteristics of Al/Pr-oxide/Ge3N4/Ge MOS capacitors, the interface state density decreases without the change of the accumulation capacitance after annealing. The TEM and TED measurements reveal that the crystallization of Pr-oxide is enhanced with annealing and the columnar structure of cubic-Pr 2O3 is formed after annealing. From the depth profiles measured using XPS with Ar sputtering for the Pr-oxide/Ge3N 4/Ge stack structure, the increase in the Ge component is not observed in a Pr-oxide film and near the interface between a Pr-oxide film and a Ge substrate. In addition, the N component segregates near the interface region, amorphous Pr-oxynitride (PrON) is formed at the interface. As a result, Pr-oxide/PrON/Ge stacked structure without the Ge-oxynitride interlayer is formed. © 2011 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.sse.2011.01.029

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担当区分：筆頭著者,　責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1143/APEX.4.026101

Web of Science

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：2011 16th International Solid-State Sensors, Actuators and Microsystems Conference, TRANSDUCERS'11  

In MEMS industry, silicon-on-insulator (SOI) wafers are gaining ground from blank silicon wafers as the main starting substrate. Tailored SOI wafers available in the market contain for example buried cavities or a buried gettering layer. Adding another layer in addition to the thermal SiO2 insulator, or replacing it with another material altogether, could be a way to tailor the properties of SOI wafers further. In this work, the direct wafer bonding of ALD TiO2, and Al2O3 for reference, is investigated, eventually in order to fabricate SOI wafers with other buried ALD oxides. © 2011 IEEE.

DOI： 10.1109/TRANSDUCERS.2011.5969474

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Applied Physics Express  

Two-dimensional nano-graphene sheets, standing vertically on carbon nanowalls (CNWs) substrates, were synthesized by multi-beam chemical vapor deposition employing three types of irradiation, Ar+ beam with tunable fluxes and energies, hydrogen (H) and fluorocarbon radicals, which could be independently controlled. The CNWs growth processes were investigated by changing the Ar+ irradiation conditions. Irradiation of Ar + ions with appropriate fluxes and energies on fluorocarbon layers evolved nanoislands for growth of the CNWs. By tuning the fluxes and energies of the incident Ar+ on amorphous carbon nanoislands, critical factors for controlling nucleation and growth of CNWs were determined. © 2010 The Japan Society of Applied Physics.

DOI： 10.1143/APEX.3.045102

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Thin Solid Films  

Formation processes of Ge3N4 by radical nitridation and electrical properties of Pr-oxide/Ge3N4/Ge structure were investigated. Stoichiometric Ge3N4 is successfully formed by the radical nitridation at temperatures from 50 to 600 °C. Change in the nitridation temperature dependence of the saturated thickness of the Ge3N4 suggests different dominant diffusion species. Leakage current density through the Ge3N4 is minimized at a nitridation temperature of 300 °C. The XPS analyses of the Pr-oxide/Ge3N4/Ge suggest decomposition of Ge3N4 during atomic layer deposition of the Pr-oxide and formation of Pr-oxynitride at the Pr-oxide/Ge interface. An interface state density in the Al/Pr-oxide/Ge3N4/Ge capacitor is drastically reduced by forming gas annealing. © 2009.

DOI： 10.1016/j.tsf.2009.10.094

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

The crystalline structures and electrical properties of high-nitrogen (N)-content Hf-Si-N films were investigated. When the N2 concentration of a sputtering ambient increases from 9.0 to 13.0%, Hf-Si-N resistivity increases by a factor of more than 105 despite the almost constant N content of the film. According to X-ray diffraction profiles and X-ray photoelectron spectra, such high-N-content Hf-Si-N films consist of Hf3N4 and Si3N4, and have energy band gaps. These results indicate that Hf3N4 and high-N-content Hf-Si-N including Hf3N4 have semiconducting features. In Pt/ Hf-Si-N/Pt structures with high-N-content Hf-Si-N, nonlinear current-voltage characteristics and hysteresis behaviors are also observed, which markedly change depending on N2 concentration and postdeposition annealing temperature. Although the elemental composition and crystalline structure hardly change, the phase separation and segregation of nanocrystallites clearly develop. Therefore, these unique electrical characteristics are attributed to current conduction at grain boundaries or Pt/Hf-Si-N interfaces. © 2010 The Japan Society of Applied Physics.

DOI： 10.1143/JJAP.49.04DA11

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Scopus

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

The formation of Pr oxide films by an atomic layer deposition (ALD) technique using Pr(EtCp)3 and H2O was investigated in this study. The ALDmode growth of Pr oxide films at a rate of 0.07 nm/cycle and a thickness variation of less than 2% on 3-in. Si wafers was achieved. Transmission electron microscopy (TEM) images and transmission electron diffraction (TED) patterns revealed that polycrystalline cubic Pr2O3 films were grown on Si(001) substrates. On the other hand, epitaxial growth of the cubic Pr 2O3 film was clearly observed on a Si(111) substrate. According to X-ray photoelectron spectroscopy (XPS) analyses, the C content of the ALD-Pr oxide film grown at 130 °C is 1.6%. Relatively fine capacitance- voltage curves were observed for the Al/ALD-Pr oxide/Si(001) capacitors. The interface state density between the 130 °C-grown ALD-Pr oxide film and the Si(001) substrate is about 1 × 1011 cm-2 eV -1. The dielectric constant of the ALD-Pr oxide film grown at 250 °C was determined to be about 18, assuming that the dielectric constant of the interlayers is similar to that of SiO2. © 2010 The Japan Society of Applied Physics.

DOI： 10.1143/JJAP.49.04DA14

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Scopus

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Ceramic Transactions  

Interactions of nitrogen plasmas with polymer surfaces were investigated using hard x-ray photoelectron spectroscopy (HXPES) to complete depth analyses of the chemical bonding states in the nano-surface layer of polymethylmethacrylate (PMMA) films via. The PMMA films were exposed to the nitrogen plasmas sustained via inductive coupling of radio-frequency (RF) power with multiple low-inductance antenna (LIA) modules. The etching rate of the PMMA films was 38 nm/min. The surface roughness of PMMA increased from 0.3 nm to 0.7 nm with increased exposure time. The HXPES was carried out for non-destructive depth analysis of chemical bonding states in the nano-surface layer of PMMA films. The HXPES results indicated that nitrogen functionalities were formed in the shallower regions up to about 27 nm from the surface without showing significant degradation of the molecular structure of PMMA due to nitrogen plasma exposure.

DOI： 10.1002/9780470917145.ch27

Scopus

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

We have investigated the interfacial control effects of the atomic layer deposition (ALD)-Al2O3 on the crystalline and electronic characteristics of LaAlO3/Ge metal-oxide-semiconductor (MOS) structures. X-ray photoelectron spectroscopic analysis Rev.ealed that Al 2O3/Ge interfaces are much more stable than LaAlO 3/Ge and La2O3/Ge interfaces for the formation of Ge oxides owing to the interfacial reaction. For the LaAlO 3/ALD-Al2O3/Ge structure, Al2O 3 interfacial layers with thicknesses less than 1 nm effectively suppress the interfacial reaction between LaAlO3 and Ge. The thickness of Ge oxides formed at the ALD-Al2O3/Ge interface decreases with increasing Al2O3 thickness and the stack structure is thermally stable against postdeposition annealing at 600 °C. These results indicate that interfacial reaction mainly arises during the sputtering-LaAlO3 deposition, not the ALD-Al2O 3 deposition. On the other hand, capacitance equivalent oxide thickness decreases with increasing interfacial ALD-Al2O3 thickness, because the formation of Ge oxides at the interface is effectively suppressed by ALD-Al2O3 interfacial layers. It can be concluded that ALD-Al2O3 is promising as an interfacial control layer between Ge substrates and high-k dielectrics.© 2009 The Japan Society of Applied Physics.

DOI： 10.1143/JJAP.48.05DA04

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

The dependences of crystalline structures and resistivity of Hf-Si-N films on nitrogen content were investigated in this study. The nitrogen (N) content of Hf-Si-N films increases with increasing N2 concentration in a N 2/Ar mixture ambient used in sputtering, and saturates to about 59% at N2 concentrations of 4.8% and above. This indicates that all Hf and Si atoms form HfN and Si3N4 in the films, respectively. From X-ray diffraction (XRD) profiles, nanocrystallites exist even in as-deposited films with saturated N content. However, they hardly grow after post deposition annealing (PDA) at 900 °C. The resistivity values are almost constant at N2 concentrations of 4.8% and below. On the other hand, they significantly increase with increasing N2 concentration above 4.8% and consequently become unmeasurable at N2 concentrations of 13.0% and above. The XRD profiles indicate that nanocrystallites segregating in those films are related to Hf3N4. © 2009 The Japan Society of Applied Physics.

DOI： 10.1143/JJAP.48.045505

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

CiNii Research

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

CiNii Research

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Thin Solid Films  

We report silicide and germanide technology for ohmic contacts and metal gates of MOSFETs in this paper. We have investigated the control technology of NiSi/Si contact properties by incorporating third elements such as Ge and C for future ULSI applications. The work function and resistivity of various Ni and Pt germanides have been also examined as metal gate materials. The low resistivity and tunable work function of these silicides and germanides are desirable for future CMOS devices. © 2008 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.tsf.2008.08.097

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

The crystal structures and electrical characteristics of Ti-Si-N metal-oxide-semiconductor (MOS) gate electrodes in the mictamict state, which is a comprehensive term referring to amorphous structures both with and without nanocrystals, were investigated. By increasing the N2 concentration of the sputtering ambient, the nitrogen (N) content of the Ti-Si-N films increased and consequently the Ti-Si-N films did not crystallize. At a N 2 concentration of more than 3.0%, the N content of the films was almost constant at about 53%, which indicates that all Ti and Si atoms deposited in the form of TiN and Si3N4, respectively. In such Ti-Si-N films with a saturated N content, only 2-3-nm-grain-size nanocrystallites formed, which were embedded in amorphous layers even after post-deposition annealing (PDA) above 900°C. At the same time, with increasing N2 concentration of the sputtering ambient, the change in the film resistivity after the PDA became smaller and the capacitance equivalent thickness (CET) fluctuation gradually ceased to occur. The work function of the mictamict Ti-Si-N gate electrodes, which were deposited in 5.0% N2 ambient and annealed at 500°C, was determined to be 4.6eV. © 2008 The Japan Society of Applied Physics.

DOI： 10.1143/JJAP.47.2420

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

CiNii Research

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

CiNii Research

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

CiNii Research

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

CiNii Research

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

CiNii Research

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Third International SiGe Technology and Device Meeting, ISTDM 2006 - Conference Digest  

Scopus

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

CiNii Research

担当区分：筆頭著者,　責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ICSICT-2006: 2006 8th International Conference on Solid-State and Integrated Circuit Technology, Proceedings  

DOI： 10.1109/ICSICT.2006.306218

Scopus

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers  

We have studied the processes of local degradation through current leakage leading to breakdown in gate SiO2 films by conductive atomic force microscopy (C-AFM). Electrical stress was applied to the SiO2 films in the form of metal-oxide-semiconductor capacitors. Leakage current spots caused by holes trapped at stress-induced defects appeared in current images of the stressed SiO2 films. During the C-AFM observation at the same area with a high electric field, currents at these leakage spots gradually increased and the breakdown finally occurred at these sites, whereas at background regions other than the leakage spots, leakage currents gradually decreased. In contrast, in the case of nonstressed SiO2 films, the breakdown occurs without showing any predictive signs. Degradation and breakdown mechanisms depending on the stress condition are discussed. © 2005 The Japan Society of Applied Physics.

DOI： 10.1143/JJAP.44.7582

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CiNii Research

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers  

A floating-gate memory with surface-nitrided Si nanocrystals buried in a SiO2 matrix has been fabricated employing radical nitridation. Si nanocrystals with a number density higher than 1 × 1012 cm -2 and an average grain size smaller than 6 nm have been grown using an ultrathin amorphous Si layer predeposited on the SiO2 surface. Since the radical nitridation of the formed Si nanocrystals effectively suppresses excess oxidation of nanocrystals during the control oxide formation, the Si nanocrystals have been successfully buried in the SiO2 matrix without losing their number density, grain size and fine spherical shape. Electrical properties of the floating-gate memory were also examined. A flat band voltage shift larger than 1 V, which is consistent with the number density of Si nanocrystals, was observed in capacitance-voltage measurements. © 2005 The Japan Society of Applied Physics.

DOI： 10.1143/jjap.44.5687

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CiNii Research

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers  

We studied local leakage currents induced in stressed gate SiO2 films and their time dependence by conductive atomic force microscopy (C-AFM). The current-voltage characteristics of the leakage currents detected in the C-AFM observations indicate Fowler-Nordheim tunneling currents enhanced by holes trapped in the stressed SiO2 films. By repeated C-AFM observations at the same area, it was found that individual spot currents decrease at different rates. This result indicates hole detrapping with different time constants from the stress-induced defects that have different features.

DOI： 10.1143/JJAP.43.4683

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CiNii Research

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers  

We have investigated microscopically the current leakage characteristics of SiO2 gate films in metal-oxide-semiconductor structure capacitors subjected to the Fowler-Nordheim (FN) constant current stress using a conductive atomic force microscope (C-AFM). Current images of C-AFM clearly reveal the leakage current spots in the samples in which the stress induced leakage current was confirmed by the macroscopic current-voltage (I-V) measurement. On the other hand, in the sample after the repeated macroscopic I-V measurement, there is a shift in threshold voltage for the appearance of current spots and its value directly corresponds to the voltage shift observed in the macroscopic capacitance-voltage measurements for this sample. The total number of current spots observable in the C-AFM scanned area critically depends on the substrate voltage: the spot number initially increases with the voltage to a certain value then decreases. The visibility of the current spot is well explained by the holes trapped locally at defect sites created in the stressed SiO2.

DOI： 10.1143/JJAP.43.1843

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CiNii Research

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics, Part 2: Letters  

We have developed a method of microscopically analyzing the degradation of gate SiO2 films in actual metal-oxide-semiconductor (MOS) devices by conductive atomic force microscopy (C-AFM). In C-AFM images of electrically stressed SiO2 films, leakage current spots on a nanometer scale were successfully observed. The observed current spots show characteristic behaviors similar to the transient stress-induced leakage current which can be detected by macroscopic electrical measurements using MOS capacitors. The appearance of the current spots is discussed on the basis of the mechanism by which holes are trapped and detrapped by stress-induced defects in SiO2 films.

DOI： 10.1143/jjap.43.l144

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CiNii Research

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers  

We have demonstrated the detection of nanometer-scale current-leakage sites in electrically stressed gate SiO2 films using a conductive atomic force microscope (C-AFM). Prior to C-AFM observations, the gate SiO 2 films in metal-oxide-semiconductor capacitors were subjected to constant-current Fowler-Nordheim (FN) stress. Details of image contrasts and the relationship between the surface topography and the current image of the SiO2 films were examined, Two types of contrast were clearly observed in the current image: a sharp bright spot reflecting local current leakage were caused by hole trapping at stress-induced defects and a fuzzy bright contrasts originating from the SiO2 thickness fluctuation. The dependence of C-AFM images on the electron injection direction during FN stress application and the SiO2 film thickness clearly reveals that the stress-induced defects are distributed in the region within 2.6 nm from the SiO2/Si substrate interface.

DOI： 10.1143/jjap.43.4679

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CiNii Research

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers  

Si nanocrystal growth using an amorphous Si (a-Si) layer pre-deposited on a SiO2 surface has been performed by ultra-high-vacuum chemical vapor deposition (UHV-CVD). It has been shown that high-density Si nanocrystals are formed by Si2H6 irradiation on to an a-Si surface and that Si atoms supplied from the a-Si layer contribute to the growth of Si nanocrystals. By changing the thickness of the a-Si layer, the number density and size of Si nanocrystals can be controlled systematically. A number density of 1.0 × 1012cm-2 and an average diameter of 9.1nm were achieved for Si nanocrystals on the SiO2/Si substrate in the case of using a 0.3-nm-thick a-Si layer. Si nanocrystals were successfully buried in a SiO2 matrix by post deposition processes and their diameters were found to range from 6 to 10nm.

DOI： 10.1143/jjap.43.3779

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CiNii Research

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

CiNii Research

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

CiNii Research

担当区分：筆頭著者,　責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Digest of Papers - Microprocesses and Nanotechnology 2004  

DOI： 10.1109/imnc.2004.245778

Scopus

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

CiNii Research

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

CiNii Research

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

CiNii Research

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers  

We have investigated the Coulomb blockade in gate-controlled hopping conduction systems made up of small-dimensional focused ion beam (FIB) implanted wires having a small non-implanted gap. Dot structures are formed in the gap by potential fluctuations caused by dispersed Ga impurities and implantation-induced defects. In the present work, the samples were subjected to two thermal treatment methods: furnace annealing at 600°C for 30 min and rapid thermal annealing (RTA) at 900°C for 30 s. In both samples, the conductance oscillates by varying the gate voltage at low temperatures, in which the nearest-neighbor hopping conduction is dominant. In the samples annealed by RTA, the oscillation amplitude becomes much larger compared with that of samples annealed at 600°C, which suggests that implantation-induced defects are annihilated by the thermal treatment at high temperatures. There coexist periodic and random peaks in the observed oscillation, which originate from the Coulomb blockade and hopping path changes, respectively. From obtained measurements, the dot size is estimated to be about 24 nm for the sample annealed at 600°C and 14 nm for the sample annealed at 900°C. The width of tunneling barrier of the sample annealed at 900°C was estimated to be about 14-17 nm. ©1999 Publication Board, Japanese Journal of Applied Physics.

DOI： 10.1143/jjap.38.1843

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CiNii Research

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers  

We have fabricated Si metal-oxide-semiconductor field-effect transistors of small dimensions using focused-ion-beam (FIB) implantation and SiO2 implantation masks with the width of 63-118 nm and have investigated the Coulomb blockade phenomena in these devices. The source and drain regions are formed by FIB implantation with a beam diameter of about 100 nm and the effective channel length is estimated to be 27-82 nm. Periodic oscillations of conductance, which are considered to be Coulomn blockade osillations, are observed at temperatures below 13K. The measured oscillation period of VG is 1.2-3.1 V and the gate capacitance is estimated to be 0.053-0.14 aF for different channel lengths. Furthermore, it is found the the oscillation period of VG increases as the channel length increases, which indicates that the dot radius decreases with increasing channel length. Large negative magnetoresistance is distinctly observed at the top of oscillation peaks and, on the other hand, only weak magnetoresistance is obtained at the bottoms. © 1999 Publication Board, Japanese Journal of Applied Physics.

DOI： 10.1143/jjap.38.7222

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CiNii Research

担当区分：筆頭著者,　責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers  

We have investigated the single-electron phenomena in p-Si hopping conduction systems with a gate electrode. The hopping conduction systems have been fabricated on Si(100) substrates by focused ion beam (FIB) implantation of Ga+ ions with a beam diameter of 0.1 μm. The samples show nearest-neighbor hopping (NNH) conduction below 30 K and the conductance is found to oscillate by changing the gate voltage in the NNH conduction region. From the period of conductance oscillation, the gate capacitance is estimated to be about 0.3-0.4 aF. The evaluated size of a dot based on the capacitance is close to the dimension of localized states in this hopping conduction system. A plateau is also observed in current-voltage characteristics between source and drain electrodes. It is considered that these phenomena originate from a Coulomb blockade and that the chain of localized hopping states acts as asymmetric multiple tunneling junctions.

DOI： 10.1143/jjap.36.4046

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CiNii Research

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Nanomaterials  

Carbon nanowalls (CNWs), which are vertically oriented multi-layer graphene sheets, were employed in surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) measurements to detect low-molecular-weight organic compounds. CNWs substrates with widely different wall-to-wall distances from 142 to 467 nm were synthesized using a radical-injection plasma-enhanced chemical vapor deposition (RI-PECVD) system with nanosecond pulse biasing to a sample stage. When survival yield (SY) values of N-benzylpyridinium chloride (N-BP-Cl) were examined, which is commonly used to evaluate desorption/ionization efficiency, a narrower wall-to-wall distance presented a higher SY value. The highest SY value of 0.97 was realized at 4 mJ/cm2 for the highest-density CNWs with a wall-to-wall distance of 142 nm. The laser desorption/ionization effect of arginine, an amino acid, was also investigated. When CNWs with a narrower wall-to-wall distance were used, the signal-to-noise (SN) ratios of the arginine signals were increased, while the intensity ratios of fragment ions to arginine signals were suppressed. Therefore, the CNWs nanostructures are a powerful tool when used as a SALDI substrate for the highly efficient desorption/ionization of low-molecular-weight biomolecules.

DOI： 10.3390/nano11020262

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEEJ Transactions on Electrical and Electronic Engineering  

DOI： 10.1002/tee.23194

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films  

DOI： 10.1116/6.0000124

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Diamond and Related Materials  

DOI： 10.1016/j.diamond.2019.107651

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ChemNanoMat  

DOI： 10.1002/cnma.201900676

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Applied Physics  

DOI： 10.1063/1.5127863

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Plasma Science and Technology  

DOI： 10.1088/2058-6272/ab84e2

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics  

DOI： 10.1116/1.5114831

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Scientific Reports  

DOI： 10.1038/s41598-019-50136-w

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.3390/c5030040

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Applied Physics Express  

DOI： 10.7567/1882-0786/ab1a58

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Plasma Processes and Polymers  

DOI： 10.1002/ppap.201800175

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics  

DOI： 10.1116/1.5083970

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Physics D: Applied Physics  

DOI： 10.1088/1361-6463/ab03c4

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEEE Transactions on Biomedical Circuits and Systems  

DOI： 10.1109/TBCAS.2018.2882472

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Physics D: Applied Physics  

For polymer electrolyte fuel cell applications, effects of Pt-nanoparticle-supported 3D carbon nanostructures, i.e. carbon nanowalls (Pt/CNWs), on electrochemical characteristics were determined by alternating current impedance analysis of resistive elements, which contribute to the oxygen reduction reaction. CNWs were fabricated by radical-injection plasma-enhanced chemical vapor deposition (RI-PECVD), and Pt catalysts were formed on the template of CNWs by supercritical fluid metalorganic chemical fluid deposition. CNWs of different wall densities were synthesized during RI-PECVD by varying the deposition pressure. The resistive elements can be consisted of three regions with different corresponding frequencies, and the resistive elements of mass diffusion, which showed up in the lowest frequency region of less than 100 Hz, increased as the wall density of CNWs increased. It was found that the wall density of CNWs was one of the essential parameters of Pt/CNWs for the electrochemical reaction involving the fluid flow and the mass transfer of active materials.

DOI： 10.1088/1361-6463/aaf8e0

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その他リンク： http://iopscience.iop.org/article/10.1088/1361-6463/aaf8e0/pdf

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

Amorphous carbon (a-C) thin films were deposited under the control of C2 radical density using radical-injection plasma-enhanced chemical vapor deposition (RI-PECVD) with CH4/H2 plasma. By actinometric monitoring of C2 emission intensities, the plasma parameters were precisely controlled by changing in CH4-containing plasma excitation power independent of H2 plasma excitation. The control of the incorporation of sp2-C clusters in the a-C films during the a-C film depositions is demonstrated by tailoring Raman positions vs. full widths at half maxima for the G band around 1580 cm-1 to the RI-PECVD parameters.

DOI： 10.7567/1347-4065/aafd49

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記述言語：日本語   掲載種別：研究論文（学術雑誌）  

DOI： 10.3390/c5010008

Web of Science

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

DOI： 10.3390/c5010007

Web of Science

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEEE International Symposium on Semiconductor Manufacturing Conference Proceedings  

Our developed non-contact method for measurement of temperature of silicon (Si) wafer by using autocorrelation-type fourier domain low coherence interferometer has advantageous in accuracy and rapid response. We demonstrate measurements in temperature for Si wafer at real-time during plasma process and in estimation of heat flux to the wafer from plasma, involving heats balanced plasma source and conductive loss in Si. The analysis indicated that other heat sources like the chamber parts with relatively high temperature impact on the duty ratio during the process with feedback control of the wafer teperture.

DOI： 10.1109/ISSM.2018.8651183

Scopus

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Physics D: Applied Physics  

The liquid-phase behavior induced by an atmospheric pressure plasma jet impinging onto water-based solutions was experimentally investigated. An increase in cavity size and circulation size resulting from an increase in impact force of the plasma jet with respect to a helium gas jet were observed through particle image velocimetry and cavity measurements. The increase in circulation size due to plasma discharge was larger than the increase solely due to an increase in jet impact force, suggesting additional shear along the liquid free surface evidenced by schlieren images of plasma-induced gas flow adherence after impingement. Liquid evaporation rate increased and mean liquid temperature decreased due to plasma effects on jet behavior. Plasma-induced decreases in liquid pH and temperature were contained within the circulation flow, leading to strong pH and temperature gradients within the liquid volume. Areas treated by the jet became acidic and remained more acidic than other portions of the liquid due to circulation vortices, highlighting the consequences of jet and liquid vessel parameters for plasma jet-liquid applications.

DOI： 10.1088/1361-6463/aaf460

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Applied Physics Express  

Carbon nanowalls (CNWs) were synthesized by radical injection plasma-enhanced chemical vapor deposition and used as scaffolds for cell culture. The proliferation of osteoblast-like cells (Saos-2) was enhanced on the CNW scaffold upon electrical stimulation (ES) with 10 Hz square pulses at a current of 226 nA. However, after incubation with ES for 10 d, differentiation of the cells toward bone formation was suppressed.

DOI： 10.7567/1882-0786/aaf469

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

DOI： 10.7567/1347-4065/aaf92a

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

Control of the bonding structure in carbon materials is achieved by a post-treatment of atmospheric pressure plasma (APP) for magnetron-sputtered carbon films. The APP post-treatment changes the films morphologically owing to the removal and modification of sp2 bonds on the basis of the near edge X-ray absorption fine structure analysis of sp2 contents. By APP post-treatment, the resulting changes in surface and bulk properties modify the optical and electrical properties of the carbon films. The control of the film properties can be utilized for various applications, such as gas sensors and solar cells.

DOI： 10.7567/1347-4065/aaec87

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Applied Physics Express  

The electrochemical durability of Pt nanoparticles-supported carbon nanowalls (Pt/CNWs) determined from potential cycle tests was 88% performance after 20 000 cycles and 50% performance around 140 000 cycles when the CNWs were fabricated by the C 2 F 6 /H 2 plasma-enhanced chemical vapor deposition system (C 2 F 6 -CNWs). Even after the extended start/stop-simulation tests of fuel cell Pt/C 2 F 6 -CNWs, Pt was aggregated; however, the morphological structure of the CNWs was maintained and no corrosion was evident from scanning electron microscopy observations and Raman analysis. For graphene-based catalyst supports, i.e., the Pt/C 2 F 6 -CNWs, graphene crystallinity is essential to extend electrochemical durability by inhibiting corrosion during fuel cell operation.

DOI： 10.7567/1882-0786/aaf0ab

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AIP Advances  

We developed a new method of GaN growth using Radical-Enhanced Metalorganic Chemical Vapor Deposition (REMOCVD) technology by which Gallium Nitride (GaN) grows at low temperatures without ammonia gas. In this method, we investigated the effect of N2/H2 plasma on the GaN substrate surface cleaning prior to the growth of homoepitaxial GaN. In-situ reflection high-energy electron diffraction (RHEED) and atomic force microscope (AFM) were used to investigate the surface morphology of the cleaned GaN substrates. The interface between GaN substrate and homoepitaxially grown GaN by REMOCVD was evaluated by transmission electron microscope and the crystal quality was evaluated by X-ray diffraction. The in-situ N2/H2 plasma cleaning at 600 °C shows a smooth surface morphology with streak diffraction lines observed by RHEED. Since the homoepitaxial growth of GaN was performed at 800 °C, the cleaned GaN substrate temperature was ramped up from 600 °C to 800 °C with and without plasma exposure to compare the effect of plasma. Homoepitaxially grown GaN on GaN substrates whose temperature was ramped up with plasma exposure showed good crystal quality with no threading dislocations at the interface. It was found that N2/H2 plasma plays a significant role in the GaN surface cleaning for good quality crystal growth.

DOI： 10.1063/1.5050819

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Micromachines  

DOI： 10.3390/mi9110565

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1109/PLASMA.2017.8496057

Web of Science

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Vacuum  

Elevated-temperature etching with CH4/H2 plasma chemistry at 300 °C improves damage-less optical properties of GaN, solving issues of degradation on near-band-edge photoluminescence intensity on plasma etching at lower temperatures than 300 °C. Damage-less etching properties in a smooth surface, high photoluminescence intensity, and substantial stoichiometric ratio of gallium and nitrogen were obtained when the CH4/H2 chemistry with substrate temperatures at 300–500 °C.

DOI： 10.1016/j.vacuum.2018.07.040

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

To satisfy the requirement for mask materials in high-temperature plasma etching, a novolac-based polymer mask was evaluated during high-temperature Cl2 plasma etching. Although the etch rate of 8 nm/min was rather high at a low temperature of 230 °C, it decreased with the increase in temperature. The aromatic ring structures were significantly modified by vacuum ultraviolet (VUV) and Cl radicals during the processes above 300 °C and transformed to a highly cross-linked amorphous carbon (a-C) layer at the surface confirmed from infrared and Raman spectra. The formation of this a-C layer improved the etching resistance of the polymer mask. On the other hand, surface roughness can also be improved after processes above 300 °C corresponding to the generation of the a-C layer. Therefore, this polymer mask is a promising candidate for high-temperature plasma etching with high etch resistance, and a smooth surface can be obtained during processes above 300 °C.

DOI： 10.7567/JJAP.57.106502

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

Plasma-induced damage (PID) on GaN was optimally reduced by high-temperature chlorine plasma etching. Energetic ion bombardments primarily induced PID involving stoichiometry, surface roughness, and photoluminescence (PL) degradation. Chemical reactions under ultraviolet (UV) irradiation and chlorine radical exposure at temperatures higher than 400 °C can be controlled by taking into account the synergism of simultaneous photon and radical irradiations to effectively reduce PID.

DOI： 10.7567/JJAP.57.06JD01

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

Quadruple mass spectrometric measurements of CH3 density during radical-injection plasma-enhanced chemical vapor deposition to consider the sp2 fraction of amorphous carbon (a-C) films were performed. The sp2 fraction of the a-C films reached a minimum of 46%, where the CH3 density was maximum for a residence time of 6 ms. The sp2 fraction of the a-C films was tailored with the gaseous phase CH3 density during the deposition. This knowledge is useful for understanding the formation mechanism of bonding structures in the a-C films, which enables the precise control of their electronic properties.

DOI： 10.7567/JJAP.57.06JE03

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

Single-walled carbon nanotubes (SWNTs) were synthesized with a high growth rate by an arc plasma method employing the electrodes made from a Ni–Y mixture catalyst. In a previous study, it was reported that the monitoring of high-crystallinity SWNT growth enabled the evaluation of the results of the optical emission spectroscopy (OES) of C2, Ni, and Y. Here, the impact of helium pressure of arc plasma on the high crystallinity of SWNTs was determined by considering the high intensity ratios of catalytic metals over C2 emissions at low helium pressures in the arc plasma.

DOI： 10.7567/JJAP.57.06JF01

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.57.040303

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.57.045101

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.57.026201

Web of Science

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/APEX.11.015102

Web of Science

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.4999256

Web of Science

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1002/ppap.201700123

Web of Science

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1116/1.4994218

Web of Science

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1088/1361-6463/aa8131

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1116/1.4997170

Web of Science

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/APEX.10.086502

Web of Science

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.56.076202

Web of Science

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1039/c7cp00489c

Web of Science

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

Electron behaviors in a pulsed dual radio frequency (RF) capacitively coupled plasma of a mixture of C4F8, O2, and Ar gases, where the DC bias of %300V in the RF-on period was imposed and synchronously increased to %1000V in the RF-off period, were investigated. The synchronous DC bias prolongs the electron density (ne) decay and provides emission of Ar at a wavelength of 750.38nm in early afterglow at 3 μs during the RF-off period of 10 kHz pulse modulation. The rapid ne decay occurred with the electron attachments to the electronegative fluorocarbons, and thus the plasma consisting of positive and negative ions was generated. The DC bias voltage seems to be applied between the electrodes and the positive ions accelerated to the top electrode, and enhanced the secondary electron generation at the top electrode surface in the RF-off period with the ion bombardments, concomitantly with the synchronous emissions.

DOI： 10.7567/JJAP.56.06HC03

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

Fabrication of an electrochemical sensor for hydrogen peroxide (H2O4) detection was demonstrated. H4O2 is a major messenger molecule in various redox-dependent cellular signaling transductions. Therefore, sensitive detection of H2O2 is greatly important in health inspection and environmental protection. Carbon nanowalls (CNWs) are composed of few-layer graphenes standing almost vertically on a substrate forming a three-dimensional structure. In this work, CNWs were used as a platform for H2O2 sensing, which is based on the large surface area of conducting carbon and surface decoration with platinum (Pt) nanoparticles (NPs). CNWs were grown on carbon fiber paper (CFP) by inductively coupled plasma-enhanced chemical vapor deposition to increase the surface area. Then, the CNW surface was decorated with Pt-NPs by the reduction of H2PtCl6. Cyclic voltammetry results indicate that the Pt-decorated CNW/CFP electrode possesses excellent electrocatalytic activity for the reduction of H2O2. Amperometric responses indicate the high-sensitivity detection capability of the Pt-decorated CNW/CFP electrode for H2O2.

DOI： 10.7567/JJAP.56.06HF03

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1088/1361-6463/aa60f7

Web of Science

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.56.035101

Web of Science

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.56.026502

Web of Science

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.4974821

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1116/1.4971171

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Web of Science

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEEE Transactions on Plasma Science  

In the field of microfluidics, it is possible to facilitate liquid transport through microsized holes with large slip lengths by lowering the friction at the interface between the flow and the inner surface of the holes. In this paper, we discuss the use of nonequilibrium atmospheric-pressure plasma to modify the surface wettability of microsized holes in glass substrates that are similar to those used as flow channels in glass microfiltration devices. In our experiments, liquid transport flows were driven by internal Laplace pressure differences based on the surface tensions of droplets placed on the front and back sides of the tested substrates.

DOI： 10.1109/TPS.2016.2571721

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Plasma Processes and Polymers  

Amorphous carbon (a-C) films are deposited using a radical-injection plasma-enhanced chemical vapor deposition (RI-PECVD) system employing a mixture of H2 and CH4 gases. Variations in the structural and electronic properties of the resulting films with changes in the residence times of radical species and molecules are investigated by varying the total gas flow rate from 50 to 400 sccm. With decreasing residence time, the deposition rate is found to gradually increase, reaching a maximum value at a residence time of 6 ms, after which a decrease was observed. Optical emission spectra showed that the relative intensity of the CH emission increased with decreasing residence time. These results indicate a change in the dominant radical species resulting from suppression of the dissociation of radicals and molecules. Increasing amorphization and an obvious increase in the Tauc gap from 0.6 to 0.9 eV are found with decreasing residence time, while there is little change in the hydrogen content of the films. From these data, it is evident that control over the structural properties and optical bandgap of a-C films can be realized by optimizing the distribution of radical species.

DOI： 10.1002/ppap.201500229

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

In hydrogenated amorphous carbon films, deposited using a radical-injection plasma-enhanced chemical vapor deposition system, the chemical bonding structure was analyzed by near-edge X-ray absorption fine-structure spectroscopy. With a change in the residence times of source gases in a reactor, whereby total gas flow rates of H2/CH4 increased from 50 to 400 sccm, sp2-C fractions showed the minimum value at 150 sccm, while H concentration negligibly changed according to the results of secondary ion mass spectroscopy. On the other hand, widths of σ∗ C-C peaks increased with decreasing gas residence time, which indicates an increase in the fluctuation of bonding structures.

DOI： 10.7567/JJAP.55.040305

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

Actual Si wafer temperatures during plasma etching processes were temporally measured using a real-time wafer-temperature monitoring system with autocorrelation-type frequency-domain low-coherence interferometry. Indeed, the Si wafer temperature, which was 20 °C before the process, rapidly increased in 10 s. Then, the temperature rise gradually slowed, but continued to increase and reached 45 °C after 600 s. This can be due to the fact that there exists a heat source for the wafer other than the plasma. Reasonably, the Si wafer was found to be sensitive to the temperature of the disk covering the area around the wafer, i.e., the focus ring. Usually, the temperature of the focus ring is not controlled and causes the radial distribution of Si wafer temperature. Consequently, the Si wafer temperature should be controlled with the temperature increase of other heat sources, especially the focus ring.

DOI： 10.7567/JJAP.55.01AB04

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Web of Science

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEEE Transactions on Semiconductor Manufacturing  

A wafer temperature feedback control system during plasma processing with rapid, precise, and real-time temperature monitoring employing frequency-domain low-coherence interferometry was developed. To keep the temperature within a specific range, plasma was actively switched on and off, controlled by signals from a monitoring system. It was applied to an organic film etching process with an H2 and N2 mixture gas plasma. The organic material etching yield from atomic hydrogen has a relatively high sensitivity to temperature, and a constant temperature is required to achieve precise etching profiles. This system maintained the wafer temperature within a few degrees for H2/N2 plasma discharges. Duty ratios per discharge gradually decreased because the temperature of the chamber component parts around the wafer increased. The trench width etched in the organic film increased with increasing wafer temperature. This is because of a temperature dependence balance between the etching reaction and protection film formation on the trench sidewall.

DOI： 10.1109/TSM.2015.2470554

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：RSC Advances  

DOI： 10.1039/c5ra12000d

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEEE Transactions on Biomedical Circuits and Systems  

The development of two new types of high-density, electroless plated microelectrode arrays for CMOS-based high-sensitivity direct bacteria and HeLa cell counting are presented. For emerging high-sensitivity direct pathogen counting, two technical challenges must be addressed. One is the formation of a bacteria-sized microelectrode, and the other is the development of a high-sensitivity and high-speed amperometry circuit. The requirement for microelectrode formation is that the gold microelectrodes are required to be as small as the target cell. By improving a self-aligned electroless plating technique, the dimensions of the microelectrodes on a CMOS sensor chip in this work were successfully reduced to 1.2 μm × 2.05 μm. This is 1/20th of the smallest size reported in the literature. Since a bacteria-sized microelectrode has a severe limitation on the current flow, the amperometry circuit has to have a high sensitivity and high speed with low noise. In this work, a current buffer was inserted to mitigate the potential fluctuation. Three test chips were fabricated using a 0.6-μm CMOS process: two with 1.2 μm × 2.05 μm (1024 × 1024 and 4 × 4) sensor arrays and one with 6-μm square (16 × 16) sensor arrays; and the microelectrodes were formed on them using electroless plating. The uniformity among the 1024 × 1024 electrodes arranged with a pitch of 3.6 μm × 4.45 μm was optically verified. For improving sensitivity, the trenches on each microelectrode were developed and verified optically and electrochemically for the first time. Higher sensitivity can be achieved by introducing a trench structure than by using a conventional microelectrode formed by contact photolithography. Cyclic voltammetry (CV) measurements obtained using the 1.2 μm × 2.05 μm 4 × 4 and 6-μm square 16 × 16 sensor array with electroless-plated microelectrodes successfully demonstrated direct counting of the bacteria-sized microbeads and HeLa cells.

DOI： 10.1109/TBCAS.2015.2479656

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PubMed

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

Plasma-induced damage (PID) during plasma-etching processes was suppressed by the application of Cl2 plasma etching at an optimal temperature of 400 °C, based on results of evaluations of photoluminescence (PL), stoichiometric composition, and surface roughness. The effects of ions, photons, and radicals on damage formation were separated from the effects of plasma using the pallet for plasma evaluation (PAPE) method. The PID was induced primarily by energetic ion bombardments at temperatures lower than 400 °C and decreased with increasing temperature. Irradiations by photons and radicals were enhanced to form the PID and to develop surface roughness at temperatures higher than 400 °C. Consequently, Cl2 plasma etching at 400 °C resulted optimally in low damage and a stoichiometric and smooth GaN surface.

DOI： 10.7567/JJAP.54.06GB04

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記述言語：日本語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

プラズマプロセスによるシリコン薄膜太陽電池の工業化がなされて以来,約35年が経つ.多くの研究者が,シリコン薄膜太陽電池を構成するアモルファスシリコン薄膜や微結晶シリコン薄膜を形成するために,プラズマ中の活性種の反応機構の構築に取り組んできた.しかしながら,シランと水素ガスを混合したプラズマによる薄膜形成に極めて重要な役割を演じている水素原子の絶対密度やその表面損失確率に関する情報はほとんど明らかにされていない.本節では,プラズマを用いたシリコン薄膜形成プロセスにおいて,真空紫外吸収分光法を用いて,水素原子の密度とその挙動を定量的に明らかにした.これらの情報の集積は,試行錯誤的なプラズマプロセスの開発から科学を基軸としたプロセス(プロセス科学)へのパラダイムシフトをもたらすことが期待される.

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

The gas phase fragmentations of perfluoro-propyl-vinyl ether (PPVE, C5F10O) are studied experimentally. Dominant fragmentations of PPVE are found to be the result of a dissociative ionization reaction, i.e., CF3+ via direct bond cleavage, and C2F3O- and C3F7O- via electron attachment. Regardless of the appearance energy of around 14.5 eV for the dissociative ionization of CF3+, the observed ion efficiency for the CF3+ ion was extremely large the order of 10-20cm-2, compared with only 10-21cm-2 for the other channels. PPVE characteristically generated CF3+ as the largest abundant ion are advantageous for use of feedstock gases in plasma etching processes.

DOI： 10.7567/JJAP.54.040301

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

Etching rates of silicon nitrides (SiN), SiO2, and poly-Si films for CH2F2 plasmas diluted with rare gases are presented by comparing the effects of flow rates of CH2F2 and dilution gases (Ar and Kr). The SiO2 etching rate was considered to be controlled by ion fluxes of the incident CHF2+ and CH2F+ under the conditions for the selective etching of SiO2 and SiN over poly-Si. Interestingly, the SiN etching rate was considerably affected by the dilution gas used. The SiN surface reaction was promoted by F-rich chemistry in the Ar-diluted CH2F2 plasma with a relatively high density of F atoms.

DOI： 10.7567/JJAP.54.040303

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Physics D: Applied Physics  

Ion densities of CH2F+ and CHF2+ were determined by dissociative ionization pathways in channels of charge exchange collisions, i.e. CH2F2 + M+→CH2F+ + F + M∗ and CHF2+ + H +M∗ [M = Ar, Kr] in CH2F2 plasmas diluted by a rare gas [M]. These channels simultaneously generated counter fragments of charge-neutral H and F atoms of interest for plasma etching processes. In Ar-diluted plasmas, CH2F+ ions predominated due to dissociative ionization between Ar+ [ca. 15.8 eV] and C-F appearance [dissociative ionization] energy [ca. 16 eV] to form CH2F+. In contrast, for Kr-diluted plasmas, C-H appearance energy [ca. 13.8 eV] predominated to produce a larger amount of CHF2+ ions due to a similar channel for charge exchange collisions between Kr+ [ca. 14 eV] and CH2F2. Thus, adding the ratio of Ar and Kr gas to CH2F2 plasmas provided control over the fraction of CH2F+ and CHF2+ ion densities.

DOI： 10.1088/0022-3727/48/4/045202

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

We have compared in detail the robust characteristics of an autocorrelation-type frequency-domain low-coherence interferometry (ACT-FD-LCI) system without a reference mirror with those of the conventional frequency-domain low-coherence interferometry (FD-LCI) system with a reference mirror. The standard deviation of temperature measurement was less than 0.04 °C at temperatures below 550 °C for a typical thickness of 480 μm, as determined from the measured optical path length. The robustness of performance against disturbances has been markedly improved, as compared with a precision of 0.28 °C in the conventional FD-LCI system with the reference mirror. In particular, we have confirmed that the ACTFD-LCI system has a large tolerance to disturbances due to dispersion and changes in the polarization of the signal light owing to the removal of the reference mirror.

DOI： 10.7567/JJAP.54.01AB03

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.4902054

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1088/0022-3727/47/42/422002

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.jcrysgro.2014.01.014

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/APEX.7.046201

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.53.040307

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.53.040305

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1088/0963-0252/23/2/025004

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

Web of Science

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.53.010305

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1371/journal.pone.0081576

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.52.11NE01

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.52.120203

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.carbon.2013.11.014

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.4827426

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Plasma Processes and Polymers  

Carbon nanowalls (CNWs) are self-assembled, free-standing, few-layered graphenenano-structures with large surface area, and thin graphene edges. For their application to nanobiotechnology, the effects of chemisorbed species on surface wettability were investigated. The surfaces of as-grown CNWs obtained using CH4/H2 mixture were hydrophilic. After Ar atmospheric pressure plasma treatments for up to 30 s, the contact angles of water droplets on the CNWs decreased from 51° to 5°, owing to a result of oxidation only at edges and surface defects. They increased up to 147°by CF4 plasma treatment at low pressure. The wide-range control of surface wettability of CNWs was realized by post-growth plasma treatments. We also demonstrated detection of bovine serum albumin using surface-modified CNWs as electrodes. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

DOI： 10.1002/ppap.201200141

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： doi:10.1088/1742-6596/441/1/012019

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.14723/tmrsj.38.325

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

The wavelength dependence of SiNx:H/Si interface defect generation caused by vacuum ultraviolet (VUV)/UV radiation from plasma etching processes was investigated. VUV radiation (λ < 200 nm) had almost no impact on the generation of defects at the SiNx:H/Si interface, since all the radiation in this wavelength range was absorbed in the upper SiN x:H film. However, UV radiation (200 < λ < 400 nm) was able to reach the underlying SiNx:H/Si interface and damage the interface. Direct UV radiation reaching the SiNx:H/Si interface dissociated the chemical bonds at the interface and generated interface-trapped charges. The estimated total energy of absorbed photons (Etotal; 200 < λ < 400 nm) at the interface layer seems to be proportional to the interface-trapped charge density (Dit) measured by capacitance-voltage measurement. However, the mechanism underlying the relationship between Etotal and Dit is not yet clear. Visible radiation (λ>400nm) had no influence on damage generation on the SiNx:H/Si structure, since the visible radiation was transmitted through upper SiNx:H film and underlying interface layer. The results revealed that UV radiation transmitted through the upper dielectrics can cause the electrical characteristics of underlying metal-oxidesemiconductor (MOS) devices to fluctuate. © 2013 The Japan Society of Applied Physics.

DOI： 10.7567/JJAP.52.05ED01

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.5772/3358

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.52.020204

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1088/0022-3727/46/10/102001

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.52.021001

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.52.01AK04

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.52.01AK05

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.4778608

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

Carbon nanowalls (CNWs) can be described as self-assembled, vertically standing, few-layered graphene sheet nanostructures. In order to demonstrate the usefulness of CNWs in fuel cell application, CNWs were directly grown on carbon fiber paper (CFP) using the inductively coupled plasma-enhanced chemical vapor deposition (ICP-CVD) method. Subsequently, highly dispersed platinum (Pt) nanoparticles were formed on the surface of CNWs using metal-organic chemical fluid deposition (MOCFD) employing a supercritical fluid (SCF). Moreover, a single proton exchange membrane (PEM) fuel cell unit using a Pt-supported CNW/CFP electrode was constructed, and its voltage-current characteristics were measured. This configuration ensures that all the supported Pt nanoparticles are in electrical contact with the external electrical circuit. Such a design would improve Pt utilization and potentially decrease Pt usage. Pt-supported CNWs grown on CFP will be well suited to the application in electrodes of fuel cells. © 2013 The Japan Society of Applied Physics.

DOI： 10.7567/JJAP.52.01AK03

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Applied Physics  

The surface loss probability of H radicals was investigated in SiH 4/H2 plasma using vacuum ultraviolet resonance absorption spectroscopy. The surface loss probability was calculated from the decay curve of the H radical density in the plasma afterglow and increased with the SiH 4 flow rate. Silicon thin films deposited on the chamber wall were analyzed to investigate the relation between the surface loss probability and the surface condition. The surface reaction of H radicals is influenced by deposition precursors, such as SiH3 radicals. The density of H radicals significantly decreased with heating of the chamber wall up to 473 K. The surface loss probability of H radicals was estimated to be ca. 1 at 473 K. Quantitative measurements of the surface loss probability of H radicals in SiH4/H2 plasma are expected to be particularly important for understanding the surface reactions that occur during the deposition of silicon thin films. © 2013 American Institute of Physics.

DOI： 10.1063/1.4773104

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：Journal of Physics: Conference Series  

We have investigated the effects of Al incorporation into a Pr-oxide/Si gate stack formed by atomic layer deposition. The PrAlOx (PAO) layers show an amorphous structure by the incorporation of Al into the Pr-oxide. The PAO sample with 10%-Al shows good C-V characteristics without a hump, and the interface state density (Dit) is as low as 5 × 1010 cm-2 eV-1. The amount of Si in the Pr-oxide film decreases by the Al incorporation. We deduce that Al incorporation into a Pr-oxide layer inhibits reaction at the interface of the PAO/Si substrate. We found that Al incorporation into the Pr-oxide is effective against the inhibition of moisture incorporation into the oxide film. The Pr(OH)3 component, estimated by x-ray photoelectron spectroscopy, increases near the surface of the Pr-oxide and PAO films with 10%-Al after 300 days, while the SiOx component does not change. The Pr(OH)3 component decreases with increasing Al incorporation. The Dit of the PAO/Si sample with 10%-Al increases after 300 days. After post metallization annealing of the sample in N 2, Dit decreases with increasing annealing temperature.

DOI： 10.1088/1742-6596/417/1/012017

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.4764065

記述言語：日本語  

掲載種別：研究論文（学術雑誌）   出版者・発行元：日本セラミックス協会  

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Applied Physics Letters  

We report the kinetic analysis of free radicals on fungal spores of Penicillium digitatum interacted with atomic oxygen generated plasma electric discharge using real time in situ electron spin resonance (ESR) measurements. We have obtained information that the ESR signal from the spores was observed and preliminarily assignable to semiquinone radical with a g-value of around 2.004 and a line width of approximately 5G. The decay of the signal is possibly linked to the inactivation of the fungal spore. The real-time in situ ESR has proven to be a useful method to elucidate plasma-induced surface reactions on biological specimens. © 2012 American Institute of Physics.

DOI： 10.1063/1.4733387

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.4729448

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

Photon-enhanced etching of SiN x:H films caused by the interaction between vacuum ultraviolet (VUV)/ultraviolet (UV) radiation and radicals in the fluorocarbon plasma was investigated by a technique with a novel sample setup of the pallet for plasma evaluation. The simultaneous injection of UV radiation and radicals causes a dramatic etch rate enhancement of SiN x:H films. Only UV radiation causes the film shrinkage of SiN x:H films owing to hydrogen desorption from the film. Capacitance-voltage characteristics of SiN x:H/Si substrates were studied before and after UV radiation. The interface trap density increased monotonically upon irradiating the UV photons with a wavelength of 248 nm. The estimated effective interface trap generation probability is 4.74 × 10 -7 eV -1·photon -1. Therefore, the monitoring of the VUV/UV spectra during plasma processing and the understanding of its impact on the surface reaction, film damage and electrical performance of underlying devices are indispensable to fabricate advanced devices. © 2012 The Japan Society of Applied Physics.

DOI： 10.1143/JJAP.51.026201

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.52.016201

記述言語：日本語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：Proceedings of SPIE - The International Society for Optical Engineering  

A volume phase holographic grating (VPHG) achieves very high diffraction efficiency up to 100% for S or P polarized light at the first diffraction order. However, diffraction efficiency of the VPHG for non-polarized light becomes low according as Bragg angle becomes large, and bandwidth of diffraction efficiency becomes narrow according as refractive index modulation of grating lattice becomes small. A volume binary grating with rectangular lattice, consists of high and low refractive index media with large or small duty ratio, is able to achieve very high efficiency nearly 100% and a wide band width for both S and P polarization light. We have successfully fabricated germanium immersion gratings of step groove shape with resolving power of 45,000 at 10 micron by using a nano-precision 3D grinding machine and ELID (ELectrolytic In-process Dressing) method. However, the method requires a large amount of machine times and efforts. We had proposed a novel immersion grating with slot shape lattice of total reflection mirrors, which achieves high performance and lower fabrication cost. We describe the photolithography and the latest plasma nano-technologies for fabrications of the novel diffraction gratings in our presentation. We also introduce birefringence volume gratings in this article. © 2012 SPIE.

DOI： 10.1117/12.925869

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

We report the kinetic analysis of radicals on fungal spores of Penicillium digitatum interacted with charged-neutral oxygen species (Oz.ast
) generated plasma discharge using real time in situ electron spin resonance (ESR) measurements. The ESR signal from the spores was observed at a g-value of around 2.004 with a line width of approximately 5G. We have successfully obtained information regarding the reaction mechanism with free radicals and realtime in situ ESR has proven to be a useful method to elucidate plasma-induced surface reactions on biological specimens. ©2012 Materials Research Society.

DOI： 10.1557/opl.2012.928

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

Two independent ovarian cancer cell lines and fibroblast controls were treated with nonequilibrium atmospheric pressure plasma (NEAPP). Most ovarian cancer cells were detached from the culture dish by continuous plasma treatment to a single spot on the dish. Next, the plasma source was applied over the whole dish using a robot arm. In vitro cell proliferation assays showed that plasma treatments significantly decreased proliferation rates of ovarian cancer cells compared to fibroblast cells. FACS and Western blot analysis showed that plasma treatment of ovarian cancer cells induced apoptosis. NEAPP could be a promising tool for therapy for ovarian cancers. © 2012 Materials Research Society.

DOI： 10.1557/opl.2012.927

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1143/JJAP.51.016202

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Applied Physics  

The modification of porous low-dielectric (low-k) SiOCH films by ashing plasma irradiation and subsequent exposure to air was investigated by in situ characterizations. Porous blanket SiOCH film surfaces were treated by a H 2 or H 2/N 2 plasma in a 100-MHz capacitively coupled plasma reactor. The individual or combined effects of light, radicals, and ions generated by the plasmas on the chemical bonds in the porous SiOCH films were characterized using an in situ evaluation and by in situ Fourier-transform infrared reflection absorption spectroscopy (IR-RAS). In situ IR-RAS analysis revealed that the number of Si-OH, Si-H, and Si-NH 2 bonds increased while the number of Si-CH 3 bonds decreased during exposure to a H 2 or H 2/N 2 plasma. Subsequent air exposure increased the number of Si-OH bonds by modifying Si-O-Si structures. The experimental results indicate that light emitted from a H 2 or H 2/N 2 plasma can break Si-CH 3 and Si-O-Si bonds and thereby generate dangling bonds. Radicals (e.g., N xH y and H radicals) can break Si-CH 3 and Si-O-Si bonds and Si-NH 2, Si-H, and Si-OH bonds could be formed. Si-NH 2, Si-H, and dangling bonds react with moisture in the air cause the formation of Si-OH bonds. The dehydroxylation reaction on Si-OH was found to be the origin of Si-O-Si network structures. The mechanism of the degradation of porous low-k SiOCH films induced by a H 2 or H 2/N 2 plasma is discussed based on the in situ characterization results. © 2011 American Institute of Physics.

DOI： 10.1063/1.3671547

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IOP PUBLISHING LTD  

We report on the high-performance decomposition and fixation of perfluoro compounds (PFCs) exhausted from dry etching processes and their reaction mechanism with the fixation material prepared from Ca(OH)(2) and Al(OH)(3) mixture. Using gas chromatography-mass spectrometry (GCMS), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and other analysis methods, it was found that PFCs were successfully decomposed and fixated by the reaction only with calcium compounds, resulting in calcium fluoride (CaF2). Aluminum compounds existing very close to calcium compounds work as a catalyst so that the reaction progresses at much lower temperatures, in the range of 650 to 750 degrees C, compared with the direct decomposition by combustion. The reaction mechanism is discussed on the basis of the proposed microscopic reaction model. These results are useful for the development of more efficient abatement systems for the greenhouse gases in the exhaust of dry etching processes. (C) 2011 The Japan Society of Applied Physics

DOI： 10.1143/JJAP.50.117301

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER INST PHYSICS  

The electronic and crystal structures of carbon nanowalls (CNWs) were analyzed using synchrotron x-rays. Although they have branchless graphene sheets with high crystallinities comparable to those of highly oriented pyrolytic graphite, they also have small amount of fluorine atoms and slightly large interlayer spacing of basal plane. Soft x-ray emission spectra indicate that CNWs have similar but not identical electronic structures to HOPG. Such the chemical and crystallographic structures might be one of factors to induce characteristic electrical features of the CNWs. (C) 2011 American Institute of Physics. [doi:10.1063/1.3659470]

DOI： 10.1063/1.3659470

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

We have investigated the control of the interfacial properties of Al 2O3/Ge gate stack structures by the radical nitridation technique. In the Al2O3/Ge structures formed by the atomic layer deposition method, the interface state density increases with the deposition temperature due to the decrease in the thickness of the Ge oxide interlayer. On the other hand, the hysteresis width of the capacitance-voltage (C-V) characteristics decreases with increasing deposition temperature, which indicates a decrease in the oxide trap density near the interface. We also investigated the control of the interfacial structure by the radical nitridation of Al2O3/Ge to form an interfacial structure after the deposition of a high-k dielectric layer. The results of X-ray photoelectron spectroscopy reveal that an Al2O3/Ge3N 4/GeO2/Ge stack structure is formed after the radical nitridation owing to the minimal oxygen diffusion into the Al2O 3/Ge interface. Furthermore, the interfacial mixing is suppressed after radical nitridation at less than 300 °C. As a result, we can decrease the interface state density of the Al2O3/Ge sample after the radical nitridation by more than one order of magnitude compared with that without radical nitridation. © 2011 The Japan Society of Applied Physics.

DOI： 10.1143/JJAP.50.10PE02

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.5772/23703

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IOP PUBLISHING LTD  

Two-dimensionally standing graphene sheets, i.e., carbon nanowalls (CNWs), were synthesized on a Si substrate employing a capacitively coupled fluorocarbon plasma-enhanced chemical vapor deposition system together with H radical injection. To apply CNWs in electronic devices and/or membrane filters, we have demonstrated the reactive ion etching (RIE) of CNWs. RIE employing H-2/N-2 gases showed that the CNW films were anisotropically etched at a relatively high rate of more than 250 nm/min. However, the 10-nm-thick interface layer between a CNW film and the Si substrate remained and the interface layer was not completely etched. In contrast, RIE employing Ar/H-2 gases enabled us to completely remove the interface layer. Ar/H-2 RIE was also carried out from the bottom surface of CNW films after exfoliating them from the Si substrate. As a result, a free-standing CNW film of 550 nm thickness without an interface layer as a membrane filter was successfully formed. (C) 2011 The Japan Society of Applied Physics

DOI： 10.1143/JJAP.50.075101

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1002/pssc.201000969

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Physical Chemistry Letters  

We report on the surface modification of poly(tetrafluoroethylene) (PTFE) as an example of soft materials and biomaterials that occur under plasma discharge by kinetics analysis of radical formation using in situ real-time electron spin resonance (ESR) measurements. During irradiation with hydrogen plasma, simultaneous measurements of the gas-phase ESR signals of atomic hydrogen and the carbon dangling bond (C-DB) on PTFE were performed. Dynamic changes of the C-DB density were observed in real time, where the rate of density change was accelerated during initial irradiation and then became constant over time. It is noteworthy that C-DBs were formed synergistically by irradiation with both vacuum ultraviolet (VUV) and atomic hydrogen. The in situ real-time ESR technique is useful to elucidate synergistic roles during plasma surface modification. © 2011 American Chemical Society.

DOI： 10.1021/jz2002937

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PubMed

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER INST PHYSICS  

An ultrahigh density over 10(13) cm(-2) of 2 nm diameter Pt nanoparticles was obtained by metal-organic chemical supercritical fluid deposition over the entire surface of vertically standing stacked graphene sheets (carbon nanowalls) on a substrate. The correlation between the surface defect density of graphene sheets and the density of Pt nanoparticles were investigated to clarify the support mechanism. The density of Pt nanoparticles increased with increase in the surface defect density. In addition, the semispherical cross-sectional shape of the nanoparticles indicated nucleation at the surface defects on the graphene sheets (98/100). (C) 2011 American Institute of Physics. [doi: 10.1063/1.3583672]

DOI： 10.1063/1.3583672

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Physics D: Applied Physics  

Nanofabrication processes employing reactive plasma, such as etching and deposition, were discussed in this paper on the basis of knowledge of reactive species in the plasma. The processing characteristics were studied based on the absolute density measurements of radicals and ions. In the case of organic low-k film etching employing N-H plasma, H and N radicals have different roles from each other; the H radicals contribute to the chemical etching, while the N radicals form the protection layer. Therefore, the ratio of H and N radical densities is an important factor for determining the etching performance. Furthermore, the radical injection technique, an active way to control the composition of radicals in the reaction field, was successfully applied to grow carbon nanowalls, self-organized, free-standing, layered graphenes. For example, with increasing density ratio of H and fluorocarbon (CFx) radicals, the density of carbon nanowalls decreases. In addition, according to the carbon nanowalls' growth by the simultaneous irradiation of CFx radicals, hydrogen atoms and Ar ions, the ion bombardment is crucial for the nucleation and vertical growth of carbon nanowalls. Identification and characterization of radicals and ions in the processing plasma could open the way to the precise controls of nano-scale plasma processing. © 2011 IOP Publishing Ltd.

DOI： 10.1088/0022-3727/44/17/174027

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

On a plasma etch reactor for a wafer of 300mm in diameter, the spatial distributions of the absolute densities of CF and CF2 radicals, electron density (ne), and the gas temperature (Tg) of N2 were measured employing the dual frequency of negative dc voltage superposed to a very high frequency (VHF) of 60 MHz capacitively coupled plasma (DS-2f-CCP) with the cyclic-(c-)C4F8/Ar/N2 gas mixture. The dc bias was superposed on the upper electrode with a frequency of 60MHz. The distributions of electron and radical densities were uniform within a diameter of about 260 mm, and took a monotonic decay in regions outside a diameter of 260mm on the reactor for 300mm wafers in the reactor. It was found that only CF2 density at the radial position between 150 and 180 mm, corresponding to the position of the Si focus ring, dropped, while CF density took a uniform distribution over a diameter of 260 mm. Additionally, at this position, the rotational temperature of N2 gas increased to be 100K larger than that at the center position. CF2 radical density was markedly affected by the modified surface loss probability of the material owing to coupling with surface temperature. © 2011 The Japan Society of Applied Physics.

DOI： 10.1143/JJAP.50.056101

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1143/JJAP.50.04DA08

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1143/JJAP.50.04DA17

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Applied Physics Letters  

In this letter, we have investigated the structural properties of thick InGaN layers grown on GaN by plasma-assisted molecular beam epitaxy, using two growth rates of 1.0 and 3.6 Å/s. A highly regular superlattice (SL) structure is found to be spontaneously formed in the film grown at 3.6 Å/s but not in the film grown at 1.0 Å/s. The faster grown film also exhibits superior structural quality, which could be due to the surface roughness suppression caused by kinetic limitation, and the inhibition of the Frank-Read dislocation generation mechanism within the spontaneously formed SL structure. © 2011 American Institute of Physics.

DOI： 10.1063/1.3574607

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.3532114

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：一般社団法人 日本真空学会  

&nbsp;&nbsp;Growth properties and electrical properties of Pr oxide films by an atomic layer deposition (ALD) technique using Pr(EtCp)₃ are discussed in this paper. Slef-limiting growth of Pr oxide films at a rate of 0.07 nm/cycle and a thickness variation of less than 2% on 3-in. Si wafers were obtained. Polycrystalline cubic Pr₂O₃ films were grown on Si(001) substrates, while epitaxial growth of the cubic Pr₂O₃ film was found on a Si(111) substrate. Relatively fine capacitance-voltage curves were obtained for the Al/ALD-Pr oxide/Si(001) capacitors. The interface state density between the 130&deg;C-grown ALD-Pr oxide film and the Si(001) substrate is about 1&times;10¹¹ cm^&minus;2 eV^&minus;1. The dielectric constant of the ALD-Pr oxide film grown at 250&deg;C was determined to be about 18, assuming that the dielectric constant of the interlayer is similar to that of SiO₂.<br>

DOI： 10.3131/jvsj2.54.110

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CiNii Books

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IOP PUBLISHING LTD  

A non-equilibrium atmospheric pressure plasma jet excited by 60-Hz ac power was diagnosed by laser Thomson and laser Raman scattering. We obtained the spatial distributions of the electron density, electron temperature, and gas temperature. The results show that the plasma can generate an electron density of up to 10(21) m(-3), an electron temperature of approximately 1 eV, and a gas temperature as low as approximately 700 K, indicating that the plasma is in the non-equilibrium state. The laser scattering diagnostic method and the obtained data are useful in the application of the non-equilibrium atmospheric pressure plasma jet. (C) 2011 The Japan Society of Applied Physics

DOI： 10.1143/APEX.4.026101

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IOP PUBLISHING LTD  

For an innovation of molecular-beam-epitaxial (MBE) growth of gallium nitride (GaN), the measurements of absolute densities of N, H, and NH3 at the remote region of the radical source excited by plasmas have become absolutely imperative. By vacuum ultraviolet absorption spectroscopy (VUVAS) at a relatively low pressure of about 1 Pa, we obtained a N atom density of 9 x 10(12) cm(-3) for a pure nitrogen gas used, a H atom density of 7 x 10(12) cm(-3) for a gas composition of 80% hydrogen mixed with nitrogen gas were measured. The maximum density 2 x 10(13) cm(-3) of NH3 was measured by quadruple mass spectrometry (QMS) at H-2/(N-2 + H-2) = 60%. Moreover, we found that N atom density was considerably affected by processing history, where the characteristic instability was observed during the pure nitrogen plasma discharge sequentially after the hydrogen-containing plasma discharge. These results indicate imply the importance of establishing radical-based processes to control precisely the absolute densities of N, H, and NH3 at the remote region of the radical source. (C) 2011 The Japan Society of Applied Physics

DOI： 10.1143/JJAP.50.01AE03

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記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

Investigation of radicals kinetic behavior and estimation of radical sticking coefficient become indispensable for establishing plasma processing control by its internal parameters. This approach is required for plasma processing of single-nanometer gate length field effect transistors and 3-diemnsional gates in particular. In our works we have developed new technique for radicals kinetic behavior investigation and its sticking coefficient estimation. Our approach is based on application of parallel plate structure in conjunction with numerical analysis. This approach allows for radicals behavior investigation apart from ions and ultraviolet photons. Moreover this approach allows for analysis role of radical direct and indirect fluxes. By comparison of measured profile thickness and simulated stuck radicals profile we were able to estimate hydrogen radical sticking probability to ArF photoresist. © 2011 IEEE.

DOI： 10.1109/SISPAD.2011.6035090

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

本研究ではSi基板上にPr(EtCp)_3,トリメチルアルミニウム(TMA)およびH_2Oを用いた原子層堆積(ALD)法を用いてPrAlO(PAO)膜を形成し,その電気的特性を明らかにした.X線光電子分光(XPS)法から,膜中に界面反応を引き起こしたSiが表面付近に偏析していることが分かり,Al導入によってそれが減少していることが分かった.このことは,Al導入によって界面反応が抑制されていることを示唆している.一方,Deep level transient spectroscopy (DLTS)の結果,Al導入によって浅い準位において界面準位密度が減少した.従って,浅い準位の界面準位密度は,界面反応に起因していると推測される.Alの導入によって界面反応の制御が可能であることを明らかにした.

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：JAPAN SOC APPLIED PHYSICS  

Carbon nanowalls (CNWs), vertically standing graphene sheets, grown by the radical injection plasma-enhanced chemical vapor deposition system were analyzed by spectroscopic ellipsometry. The refractive indexes (n), extinction coefficients (k), and optical band gaps (E(g)) of evolutionary growth layers were evaluated using the Tauc-Lorentz model with the effective medium approximation. It was observed that an amorphous carbon interfacial layer with n of 1.9-2.0 was formed prior to the growth of CNWs with n of 1.2-1.5. Moreover, the imaginary parts of complex dielectric functions analyzed using the Tauc-Lorentz model indicate the possibility that the CNWs have semiconducting features. (C) 2010 The Japan Society of Applied Physics

DOI： 10.1143/JJAP.49.060220

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Applied Physics Letters  

Praseodymium (Pr) oxide films were grown by metal-organic chemical-vapor-deposition (CVD) using Pr (EtCp) 3. Using H 2 O as an oxidant, Pr2 O3 films with columnar structures are formed and its C concentration can be reduced to about one-tenth compared with the case using O2. Activation energy of 0.37 eV is derived for this CVD using H2 O. This CVD-Pr oxide film deposited at 300 °C has a dielectric constant of 26±3. Furthermore, conduction band offset of 1.0±0.1 eV and trap levels of 0.40±0.02 and 0.22±0.02 eV in the CVD-Pr2 O3 /Si structure were also determined by current conduction characteristics. © 2010 American Institute of Physics.

DOI： 10.1063/1.3275706

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記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：JAPAN SOC APPLIED PHYSICS  

A 60 Hz alternating current excited atmospheric-pressure plasma with an ultrahigh electron density of over 10(16) cm(-3) employing H-2/Ar [p(H-2)/p(H-2 + Ar) 1-3%] gases was used to reduce copper oxides on copper. The remote plasma reduced CuO and Cu2O at room temperature. The ground-state hydrogen (H) radical density in the atmospheric-pressure plasma was measured by vacuum ultraviolet absorption spectroscopy using a micro hollow cathode lamp. The ratio of reduction of amount of CuO flux to the H radical flux was determined from the measured H radical density and gas temperature. (C) 2010 The Japan Society of Applied Physics

DOI： 10.1143/APEX.3.126101

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

Controlling factors of crystalline and electronic structures of carbon nanowalls were investigated in this study. Precise measurements and controls of radicals and ions in the plasma make the controlled syntheses of CNWs possible. For example, density ratios of hydrogen (H) and carbon atoms are essential to determine the density and height of CNWs. Ar+ ion irradiation is also important for vertical-growth of graphene sheets. Vertical-growth of graphene sheets could occur only under Ar+ ion irradiation with suitable energy and flux for each process. On the other hand, by N-2 gas addition to C2F6/H-2/Ar mixture ambient, the CNWs with n-type conducting properties can be formed. These results obtained in this study suggest that the CNWs are promising as new functional device materials in various applications.

DOI： 10.1109/TENCON.2010.5686534

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：AMER CERAMIC SOC  

Interactions of nitrogen plasmas with polymer surfaces were investigated using hard x-ray photoelectron spectroscopy (HXPES) to complete depth analyses of the chemical bonding states in the nano-surface layer of polymethylmethacrylate (PMMA) films via. The PMMA films were exposed to the nitrogen plasmas sustained via inductive coupling of radio-frequency (RF) power with multiple low-inductance antenna (LIA) modules. The etching rate of the PMMA films was 38 nm/min. The surface roughness of PMMA increased from 0.3 rim to 0.7 urn with increased exposure time. The HXPES was carried out for non-destructive depth analysis of chemical bonding states in the nano-surface layer of PMMA films. The HXPES results indicated that nitrogen functionalities were formed in the shallower regions up to about 27 nm from the surface without showing significant degradation of the molecular structure of PMMA due to nitrogen plasma exposure.

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ELSEVIER SCIENCE SA  

Plasma surface treatment of polymers has been carried out with argon/oxygen mixture plasmas driven by multiple low-inductance antenna units. Kinetic energy distribution of argon ions from the argon/oxygen mixture plasmas onto polymers showed considerable suppression of ion energies sufficiently less than 10 eV. Polyethyleneterephthalate (PET) films were exposed to argon/oxygen mixture plasma for 1-5 min on a water-cooled substrate holder. The etching depth of PET surface increased with increasing plasma-exposure time and the etching rate was 118 nm/min. Surface roughness of PET surface (root-mean-square value) increased from 0.5 nm to 2.7 nm with increasing plasma-exposure time from 0 min (original sample) to states of the PET surface. The HXPES analyses exhibited nano-surface modification of the PET surface without suffering degradation of molecular structures beneath. (C) 2009 Elsevier B.V. all rights reserved.

DOI： 10.1016/j.tsf.2009.07.161

Web of Science

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Solid-State Electronics  

We have proposed a novel method to form by microfabrication a uniaxial tensile strained Ge layer due to the elastic strain relaxation of a Si1-xGex buffer layer on a Si(0 0 1) substrate. A fully strain-relaxed Ge layer on a compressive strained Si0.60Ge0.40 was epitaxially grown on Si(0 0 1) substrate and striped mesa lines were fabricated with a line width of 250 nm along the [1 1 0] direction. The strain of the Si0.60Ge0.40 layer was found to be elastically relaxed only along the direction perpendicular to the lines and a uniaxial tensile strained Ge layer was thus formed. The value of tensile strain of the Ge layer is estimated to be 0.25%. © 2009 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.sse.2009.08.001

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

高移動度Geチャネルを有するmetal-oxide-semiconductor(MOS)型トランジスタの実現に向け、熱処理や溶液処理に対してロバストな高誘電率金属酸化膜/Ge構造の構築が求められている。本研究では、高誘電率金属酸化膜/Ge構造における界面層として期待されるGe_3N_4膜に関し、ラジカル窒化法による形成過程を明らかにし、更にPr酸化膜/Ge_3N_4/Ge構造の電気的特性を評価した。ラジカル窒化法では、50-600℃の広い温度範囲でStoichiometryなGe_3N_4が形成された。一方、飽和膜厚の窒化温度依存性は窒化温度によって異なり、Ge_3N_4形成に支配的な拡散種が異なると考えられる。またAu/Ge_3N_4/Ge構造におけるリーク電流密度は、窒化温度300℃において最も小さいことがわかった。ラジカル窒化法と原子層堆積法によってPr酸化膜/Ge_3N_4/Ge構造を作製した場合、Pr酸化膜/Ge界面にはPr酸窒化膜が形成される。またAl/Pr酸化膜/Ge_3N_4/Ge MOSキャパシタでは、H_2およびN_2雰囲気での熱処理によって界面準位密度が大幅に減少することが分かった。

記述言語：英語   掲載種別：研究論文（学術雑誌）  

GeチャネルMOSFETは高速動作および低電圧動作デバイスとして期待され、また一方で、high-k材料によるゲート絶縁膜はEOTの低減に有効であり、high-k/Ge構造のMOSFETは次世代デバイスとして有望視されている。しかしながら、high-kゲート絶縁膜とGe基板との界面反応によって、ゲート絶縁膜の誘電率は低下し、また、界面準位密度は増加する。そこで、high-kゲート絶縁膜とGe基板との界面にALD法によって形成した極薄のAl_2O_3界面制御層を挿入し、その効果について検討した。なお、本研究ではhigh-kゲート絶縁膜としてLaAlO膜を用いた。厚さ1nm以下のAl_2O_3界面制御層によってGe界面での界面反応は効果的に抑制でき、界面反応によって形成されたGe-oxide層はAl_2O_3界面制御層の厚さの増加とともに減少することが分かった。また、0.4nm程度の厚さのAl_2O_3界面制御層において界面準位密度の低減効果を確認した。さらに、600℃の熱処理に対しても構造は変化せず、熱的にも安定であることが分かった。

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

Pr(EtCp)_3を用いた原子層堆積法(ALD)によるPr酸化膜の成長手法について研究を行い,ウェハー面内での膜厚ばらつきが2%以下であるPr酸化膜のALD成長を実現した.同ALDでは主として立方晶のPr_2O_3が形成したが,Si(100)基板上のPr_2O_3膜が多結晶構造であるのに対し,Si(111)基板上では立方晶Pr_2O_3がエピタキシャル成長することがわかった.一方,Al/ALD-Pr_2O_3/Si(100)およびAl/ALD-Pr_2O_3/Si(111)MOSキャパシタの容量-電圧特性によれば,ALDによって成長した立方晶Pr_2O_3の比誘電率は12.3〜16.8であった.電子銃蒸着法や化学気相蒸着法(CVD)で成長したPr酸化膜の結晶構造および成長条件との比較から,ALDプロセスにおいてH_2O分圧を最適化することにより,Pr酸化膜の結晶構造が制御可能であると考えられる。

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

The annealing temperature and thickness dependences of electrical properties of mictamict Ti-Si-N gate metal-oxide-semiconductor (MOS) capacitors, and their relationships with the crystalline structure were investigated. The nanocrystallites in mictamict Ti-Si-N films sputtered in over 3.0% N2 ambient hardly grow even after postdeposition annealing (PDA) at temperatures below 900 °C. As the N2 concentration increases up to 3%, the resistivity of the Ti-Si-N films increases owing to an increase in the amount of Si3N4 components and the development of the amorphization. On the other hand, the resistivity decreases with increasing N2 concentration above 3%. This is attributed to the formation of Ti3N4 components, as revealed by X-ray photoelectron spectroscopy (XPS) analysis. The changes in resistivity and effective work function are also extremely small. Additionally, even when the Ti-Si-N film thickness is reduced to 5 nm, the Pt/Ti-Si-N stacked gate electrode maintains almost the same effective work function (4.6 eV). © 2009 The Japan Society of Applied Physics.

DOI： 10.1143/JJAP.48.04C012

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記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：一般社団法人 日本MRS  

We have investigated the anisotropic strain structure of micro-patterned Ge/Si_1-xGe_x mesa lines. The elastic strain-relaxation of a Si_1-xGe_x layer by micro-patterning induces an uniaxial tensile strain into a Ge layer only for the direction perpendicular to the line. The pattern size dependence on the behavior of the elastic strain-relaxation of Si_1-xGe_x layers is analyzed by FEM. Additionally, the XRD results for micro-patterned samples suggest that the overetching depth of the Si substrate also influenced the strain-relaxation of the Si_1-xGe_x layers and the tensile-strain value of the Ge layers.

DOI： 10.14723/tmrsj.34.305

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Thin Solid Films  

High-density and similarly-sized Si nanodots were formed by annealing ultra-thin amorphous Si (a-Si) films deposited on SiO2/Si substrates in vacuum. Dependences of density and diameter of the Si nanodots on the a-Si film thickness and, annealing temperature and time were investigated by scanning electron microscopy. It is found that drastic increase (decrease) in the density (diameter) occurred at an a-Si thickness of 1 nm. By agglomeration of sub-nanometer thick a-Si films, a density larger than 1012 cm- 2, an average diameter smaller than 5 nm, and a dispersion of diameter less than 15% were achieved. © 2008 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.tsf.2008.08.079

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

担当区分：筆頭著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：ECS Transactions  

Formation of Ge3N4 on Ge(001) substrates by nitrogen radicals and their thermal stability were investigated in this study. A Ge 3N4/Ge structure with a root-mean-square surface roughness of 0.18 nm is successfully formed by layer-by-layer manner at a substrate temperature of 300°C. In contrast, island growth and thermal decomposition of Ge3N4 occur during the nitridation at 600°C, and consequently island structures and locally-flat areas are formed. Ge 3N4 thickness is saturated at a certain nitridation time and, not only saturation times but also saturation thicknesses are different depending on plasma condition. By a 2-step nitridation in which the nitridation at 300°C and 600°C for 900 sec were sequentially subjected to Ge surfaces, a Ge3N4 thickness much larger than that at the single-step nitridation can be obtained without surface roughening. ©The Electrochemical Society.

DOI： 10.1149/1.2986828

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担当区分：筆頭著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1143/JJAP.46.1865

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1143/JJAP.46.71

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1088/0268-1242/22/1/S31

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記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

&nbsp;&nbsp;Initial stage of processes and energy bandgap formation in nitridation of silicon surfaces using nitrogen radicals have been studied. According to scanning tunneling microscopy observations and scanning tunneling spectroscopy measurements, at the initial stage of nitridation, linear defects perpendicular to dimmer rows were formed to coincide with an initial nitridation reaction preferentially at backbonds of surface Si atoms. After the nitride formation, the surface roughness depends only on substrate temperature regardless of radio frequency (RF) power, which means that the growth mode of nitrides is attributed to the surface migration. Contrary, the energy bandgap of silicon nitrides is significantly affected by not only substrate temperature but also RF power. Absorption and emission spectroscopy results suggest that the contribution of the excited-state nitrogen atoms to the nitridation increases with increasing the RF power. Control of surface migration and radical species is crucial to form the monolayer-thick nitride layer with both an atomically flat surface and a wide energy bandgap.<br>

DOI： 10.3131/jvsj.50.665

Scopus

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：ECS Transactions  

We report silicide and germanide technology for ohmic contacts and metal gates of MOSFET applications. We have investigated control of crystalline and electrical properties of NiSi/Si contacts by the incorporation of third elements. Thermal stability and electrical properties of NiSi/Si contacts are effectively controlled by the incorporation of Ge and C. We have also systematically investigated the work function and the resistivity of various Ni and Pt germanides as metal gate materials. The low resistivity and tunable work function of these germanides and silcides are desirable for future CMOS devices. © The Electrochemical Society.

DOI： 10.1149/1.2778377

Scopus

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：International Journal of High Speed Electronics and Systems  

The chemical structures of SiO2/Si interfaces were studied by photoelectron spectroscopy using high-brilliance soft X-ray with photon energy ranging from 500 to 1500 eV at Super Photon ring 8 GeV(SPring-8) and it is able to probe a depth of about 1.2 to 3 nm with energy resolution of 100 meV. On the other hand, high-brilliance hard X-ray with photon energy ranging from 6 to 10 keV is able to probe a depth of about 8.5 to 12.5 nm with energy resolution of 100 meV. Hard photoelectron spectroscopy are particularly useful for studying the composition and the chemical structure of transition layer at high-k dielectric/silicon interface. © World Scientific Publishing Company.

DOI： 10.1142/S0129156406003680

Scopus

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers  

We have investigated an initial stage of titanium nitride (TiN) growth on SiO2 substrates by ultrahigh-vacuum chemical vapor deposition with TiCl4 and NH3 as source materials. The behaviors of nucleation and grain growth of TiN have been clarified by atomic force microscopy and transmission electron microscopy. It was found that TiN film formation at an initial stage consists of three stages, which are characteristic of the lateral and subsequent vertical growth processes of grains. Deposition time dependence of the lateral growth of TiN grains clearly indicates that a process at 550°C is limited by the surface reaction, irrespective of the TiCl4 flow rate and a pretreatment for the substrates before the deposition. The pretreatment affects in the generation of additional nucleation sites on the SiO2 surface but does not affect the mechanisms of nucleation and grain growth. © 2006 The Japan Society of Applied Physics.

DOI： 10.1143/JJAP.45.49

Web of Science

Scopus

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：ECS Transactions  

DOI： 10.1149/1.2355823

Scopus

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s10165-005-0420-z

Scopus

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

CiNii Books

CiNii Research

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

電流検出型原子間力顕微鏡法(Conductive Atomic Force Microscopy : C-AFM)を用いて、ゲート絶縁膜における局所リ-ク電流をナノスケール観察し、絶縁膜の信頼性劣化機構を解明した。MOSキャパシタにおいてストレス印加したゲートSiO_2膜をC-AFM観察したところ、電流像に局所なりーク電流スポットを観測がされ、その電流-電圧特性の解析などからストレス誘起欠陥に起因する局所リーク電流であることがわかった。更に、ストレス誘起欠陥における電荷充放電現象とマクロなデバイス特性劣化との相関、局所リーク電流と絶縁破壊現象との関連が明らかになった。また、高誘電率絶縁膜において、電流リークパスと結晶構造との相関を明らかにした。

記述言語：英語   掲載種別：研究論文（学術雑誌）  

次世代ゲート絶縁膜として期待されるシリコン窒化膜について、ラジカル窒化法における初期成膜過程をSTMならびにSTSによって解析した。ラジカル窒化過程では、成膜様式(層状成長または島状成長)は窒化種に依存せず、成膜温度のみに依存するが、エネルギーバンドギャップはラジカルガンの高周波電源電力の変化に伴う窒化種の変化に強く依存することがわかった。原子レベルで平坦で、大きなエネルギーバンドギャップを持つラジカル窒化膜の形成には、窒化種の制御が重要であることがわかった。

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：Proceedings - Electrochemical Society  

Next-generation metal-oxide-semiconductor (MOS) devices will require metal gate electrodes to eliminate some problems which conventional poly-Si gate electrodes have, such as gate depletion, high resistivity, chemical reaction with high-k dielectrics and so on. In this study, we have investigated the characteristics of NiGe gate electrodes for MOS devices. An interface between NiGe and gate SiO2 films was highly stable after post-deposition annealing at high temperature. The work function of the NiGe was found to depend on the annealing temperature and obtained to be ranging from 4.79 eV to 4.94 eV, which stands by the valence band side. The sheet resistance was an order of magnitude lower than that of the conventional poly-Si gate. Because of these features, NiGe is a promising candidate for PMOS device.

Scopus

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

電流検出型原子間力顕微鏡法(Conducting Atomic Force Microscopy :C-AFM)を用いて、Metal-Oxide-Semiconductor(MOS)キャパシタで観測される絶縁膜劣化を、ナノスケールで直接観察する手法を開発した。定電流ストレスを印加したシリコン酸化膜を本手法によって観察した結果、Transient Stress-Induced Leakage Current (Transient-SILC)と考えられる局所リーク電流スポットが観測された。これにより、ストレス誘起される膜中欠陥の局所性と分布、それらに起因した局所的なリーク伝導機構が実験的に明らかになった。

掲載種別：研究論文（学術雑誌）  

DOI： 10.2116/analsci.19.79

PubMed

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：Digest of Papers - Microprocesses and Nanotechnology 2003 - 2003 International Microprocesses and Nanotechnology Conference, MNC 2003  

In this paper, we have developed a novel growth of Si nanocrystals by using molecular beam deposition and post-growth oxidation. Formation of Si dots with a high number density (about 1/spl times/10/sup 12/ cm/sup -2/) and a small grain size (less than 10 nm in diameter) has been demonstrated. Memory operations of devices using these Si dots were also examined.

DOI： 10.1109/IMNC.2003.1268498

Scopus

担当区分：筆頭著者   記述言語：日本語  

DOI： 10.11501/3152127

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：1999 International Microprocesses and Nanotechnology Conference  

We have investigated Coulomb blockade phenomena in low-dimensional Si metal-oxide-semiconductor field-effect-transistors (MOSFETs) with the very small length and very narrow width of channel regions, which are fabricated using e-beam lithography, dry etching and focused ion beam (FIB) implantation. Coulomb blockade phenomena have been found in Si nano-wires and narrow channel Si MOSFETs. In our previous study, the conduction mechanism and Coulomb blockade phenomena in one-dimensional p-type Si wires formed by FIB implantation has been reported. In the present study, we have successfully fabricated low-dimensional p-channel Si MOSFETs, whose source/drain regions with a width of 100 nm are formed by selective FIB implantation. Coulomb blockade phenomena and magnetoresistance are examined using the sample, as a function of channel length.

DOI： 10.1109/IMNC.1999.797509

Scopus

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Web of Science

記述言語：日本語 著書種別：学術書

CiNii Books

担当ページ：.   記述言語：日本語

J-GLOBAL

J-GLOBAL

記述言語：英語   掲載種別：速報，短報，研究ノート等（学術雑誌）   出版者・発行元：IOP PUBLISHING LTD  

The InN films were deposited on GaN surfaces at a low temperature of 200 degrees C by radical-enhanced metal organic chemical vapor deposition (REMOCVD). The REMOCVD system can provide N radicals from the plasma of a N-2-H-2 mixture gas without using ammonia. Two types of GaN substrate, bulk GaN and GaN on Si(111), were used. The growth mode was modeled as a step flow on the basis of surface morphology observation by atomic force microscopy. (C) 2017 The Japan Society of Applied Physics

DOI： 10.7567/JJAP.56.06HE08

Web of Science

記述言語：日本語   掲載種別：記事・総説・解説・論説等（学術雑誌）  

J-GLOBAL

記述言語：英語   掲載種別：速報，短報，研究ノート等（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

Deep ultraviolet (UV) photons emitted from Cl2 plasmas become a critical cause of degradation in both photoluminescence (PL) properties and surface stoichiometry as a result of plasma-induced damage on GaN films in Cl2 plasma etching at high temperatures. The damages were formed thermally by photon-irradiations of plasma UV emissions with wavelengths of >258-306 nm from Cl2 plasma at temperatures greater than 500 °C. The damage were observed with a depth of approximately 3.2 nm. The PL property degraded by the UV emission-induced damage at an early period of plasma etching and reached a constant value.

DOI： 10.7567/JJAP.56.096501

Scopus

J-GLOBAL

記述言語：日本語   出版者・発行元：化学工学会  

CiNii Books