研究者詳細 - 石川　健治

論文 - 石川　健治

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Dry Process FOREWORD 査読有り

Shirafuji, T; Kinoshita, K; Akatsuka, H; Eriguchi, K; Ichikawa, T; Ichiki, T; Ishijima, T; Ishikawa, K; Karahashi, K; Kurihara, K; Sekine, M

JAPANESE JOURNAL OF APPLIED PHYSICS 59 巻 ( SJ ) 2020年6月

Synthesis of isolated carbon nanowalls via high-voltage nanosecond pulses in conjunction with CH<sub>4</sub>/H<sub>2</sub> plasma enhanced chemical vapor deposition 査読有り

Ichikawa, T; Shimizu, N; Ishikawa, K; Hiramatsu, M; Hori, M

CARBON 161 巻頁： 403 - 412 2020年5月

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

Carbon nanowalls (CNWs) are vertically standing, interconnecting flake- or wall-like collections of graphene sheets. In the present work, this material was synthesized by applying precisely controlled high-voltage nanosecond pulses to a substrate using an inductor energy storage circuit in a radical-injection plasma-enhanced chemical vapor deposition system, employing a CH4/H2 plasma. The resulting interconnected networks had a low density of CNWs with large average wall-to-wall distances. During the application of short-period pulses, the entire substrate surface was uniformly activated, thus enhancing the adsorption of carbon precursors and preventing CNW nucleation. As a result, an amorphous carbon film covered the surface of the substrate and a low CNW density was obtained with average wall-to-wall distances greater than 700 nm. On the basis of these results, the growth mechanism of CNWs was modeled.

DOI： 10.1016/j.carbon.2020.01.064

Gas-phase and film analysis of hydrogenated amorphous carbon films: Effect of ion bombardment energy flux on sp<SUP>2</SUP> carbon structures 査読有り

Sugiura, H; Ohashi, Y; Ishikawa, K; Kondo, H; Kato, T; Kaneko, T; Takeda, K; Tsutsumi, T; Hayashi, T; Sekine, M; Hori, M

DIAMOND AND RELATED MATERIALS 104 巻 2020年4月

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

Hydrogenated amorphous carbon (a-C:H) films comprise nanoclustering graphites (nc-G), fused aromatic rings (nR), and olefinic chain clusters (nC) of sp2-bonded carbons in an sp3 matrix. In this study, the sp2 composition of the nc-G, nR and nC in a-C:H films is found to be determined by the ion bombardment energy flux (ΓEi), which can be estimated as the product of ion bombardment energy and ion flux onto the deposited surface, in plasma-enhanced chemical vapor deposition using a plasma mixture of H2 and CH4 gases with the H radical injection method. The sp2 composition is analyzed using Raman spectroscopy and near-edge X-ray absorption structure spectroscopy. a-C:H becomes increasingly graphitized with increasing ΓEi. The precise control of the sp2 C structure composition can be achieved by controlling the very-high-frequency input power and radio frequency input bias power via the ion flux and ion bombardment energy.

DOI： 10.1016/j.diamond.2019.107651

In-Liquid Plasma Synthesis of Nanographene with a Mixture of Methanol and 1-Butanol 査読有り

Ando, A; Ishikawa, K; Takeda, K; Ohta, T; Ito, M; Hiramatsu, M; Kondo, H; Sekine, M; Hori, M

CHEMNANOMAT 6 巻 ( 4 ) 頁： 604 - 609 2020年4月

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

Nanometer-size graphene sheets (nanographene) were synthesized by the in-liquid plasma method employing a mixture of alcohols. Pure methanol in-liquid plasma was found to not synthesize any nanographene. Pure ethanol synthesized nanographene with high crystallinity. Highly crystalline nanographene with a narrow full width-half maximum of the Raman scattering G-band (FWHMG) was obtained by mixing 1-butanol with methanol. This is due to the formation of carbon ring structures being inhibited by the addition of methanol. The ratio of added methanol determined the nanographene crystallinity and yield under a trade-off relationship, allowing the crystallinity and nanographene yield to be controlled by controlling the ratio. Gas chromatography-mass spectrometric analysis of by-products in the liquids’ supernatant showed that the crystallinity of the synthesized nanographene correlated with the ratio of carbon over oxygen of the alcohol precursors (C/O), i. e., the amount of hydroxyl groups in the liquids, and hence controlling the C/O ratio can be used to control the graphene crystallinity in the in-liquid plasma synthesis.

DOI： 10.1002/cnma.201900676

Interaction of oxygen with polystyrene and polyethylene polymer films: A mechanistic study 査読有り国際共著

Fukunaga, Y; Longo, RC; Ventzek, PLG; Lane, B; Ranjan, A; Hwang, GS; Hartmann, G; Tsutsumi, T; Ishikawa, K; Kondo, H; Sekine, M; Hori, M

JOURNAL OF APPLIED PHYSICS 127 巻 ( 2 ) 2020年1月

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

In this work, first principles calculations combined with advanced surface diagnostics are used to unravel the mechanisms of plasma oxygen interaction with organic films of interest for advanced patterning in semiconductor device manufacturing. Results from a combination of x-ray photoelectron spectroscopy (XPS) diagnosed oxygen plasma exposed polystyrene films and first principles modeling of organic films (polystyrene, polyethylene, and derivatives) provide insights into how organic films are oxidized by oxygen atoms. XPS measurements show the rapid formation of C-O structures and their saturation after oxygen exposure on both pristine and argon bombarded polystyrene samples. Quantum mechanics calculations confirm that C-OH formation can be immediate without recourse to previously formed dangling bonds. Multiple oxygen impacts are required for scission of pristine ethylene carbon strands. Therefore, ethylene films can be converted to polyols that are stable, whereas more likely strands are broken before polyol formation through the formation of water and C=O. On the contrary, intermediate compounds with adjacent C=O bonds are not likely to form stable structures. The combination of XPS measurements and modeling implies that the oxidation of polystyrene and polyethylene is self-limiting on both hydrogen saturated and dehydrogenated (after argon ion plasma bombardment) surfaces.

DOI： 10.1063/1.5127863

Inactivation mechanism of fungal spores through oxygen radicals in atmospheric-pressure plasma 査読有り

Ito M., Hashizume H., Oh J.S., Ishikawa K., Ohta T., Hori M.

Japanese Journal of Applied Physics 60 巻 ( 1 ) 頁： 010503 2020年

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

A brief history of the development of our plasma technology for the disinfection of agricultural harvests is presented in this review. We focused on the influence of reactive oxygen species (ROS), e.g. ground-state oxygen atoms [O(3P j )], excited-state oxygen molecules [O2(1Δg)], and ozone (O3), generated from atmospheric-pressure plasmas on the inactivation of fungal spores under dry conditions. For elucidating the inactivation mechanisms, it is essential to reveal the key ROS. Using some powerful tools, we revealed that the dose of O(3P j ) strongly correlates with the inactivation of fungal spores when compared to those of another ROS, such as O2(1Δg) and O3. The balance of antioxidants in the spores is possibly modulated by O(3P j ), leading to oxidation of organelles in spores. Herein, we introduce and discuss how O(3P j ) contributes to the inactivation of fungal spores associated with in situ diagnostics of plasma generated ROS and in situ intracellular observations of a few fungal spore species.

DOI： 10.35848/1347-4065/abcbd1

Leukocyte depletion and size-based enrichment of circulating tumor cells with pressure-sensing microfiltration system 査読有り

Kuboyama D., Onoshima D., Kihara N., Tanaka H., Hase T., Yukawa H., Ishikawa K., Odaka H., Hasegawa Y., Hori M., Baba Y.

21st International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2017 頁： 882 - 883 2020年

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：21st International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2017

We present a study of blood microfiltration system towards optimal approach of non-invasive liquid biopsy for cancer detection by circulating tumor cells (CTCs). Filtration behavior of a microfilter was experimentally analyzed for tumor cell isolation from leukocytes in whole blood. This approach achieved an average of >96% recovery of spiked tumor cells and >99% total leukocytes depletion.

Cell deposition and isolation with micropipette control over liquid interface motion in microfluidic channel 査読有り

Onoshima D., Yukawa H., Hattori Y., Ishikawa K., Hori M., Baba Y.

21st International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2017 頁： 679 - 680 2020年

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：21st International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2017

We developed a microfluidic chip for depositing single cells in microwells using simple micropipette operation. Cells were delivered to microwells by the meniscus motion of liquid interface. The residue deposits of cells were redistributed with air injection, and the isolated single cells were stored in microwells. Different microwell sizes and depths were studied to evaluate the trapping possibility of cells. Medium replacement and cell viability staining with the isolated single cells were achieved in microwells.

Etching characteristics of PECVD-prepared SiN films with CF<sub>4</sub>/D<sub>2</sub> and CF<sub>4</sub>/H<sub>2</sub> plasmas at different temperatures 査読有り

Hsiao, SN; Nguyen, TTN; Tsutsumi, T; Ishikawa, K; Sekine, M; Hori, M

2020 INTERNATIONAL SYMPOSIUM ON SEMICONDUCTOR MANUFACTURING (ISSM) 2020-December 巻 2020年

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 International Symposium on Semiconductor Manufacturing Conference Proceedings

The dependences of plasmas (CF4/D2 and CF4/H2) on etch rates of the PECVD SiN films at different substrate temperatures were investigated. The CF4/D2 plasma exhibited higher etch rates than that for the CF4/D2 plasma at room temperature and higher. The optical emission spectra showed that the CF polymerization, F and Balmer emissions were stronger in the CF4/D2 plasma, by comparing with the CF4/H2 plasma. A thinner fluorocarbon thickness with a lower F/C ratio was found in the sample proceeded by the CF4/H2 plasma. The fluorocarbon thickness and gas phase concentration were not responsible for the increase of etch rate in the CF4/D2 plasma. The abstraction of H inside the SiN films by deuterium and hydrogen dissociation were considered to be important for the etching of the Si-H bond rich SiN films.

DOI： 10.1109/ISSM51728.2020.9377537

Rapid thermal-cyclic atomic-layer etching of titanium nitride in CHF<sub>3</sub>/O<sub>2</sub> downstream plasma 査読有り

Shinoda, K; Miyoshi, N; Kobayashi, H; Izawa, M; Ishikawa, K; Hori, M

JOURNAL OF PHYSICS D-APPLIED PHYSICS 52 巻 ( 47 ) 2019年11月

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

Isotropic atomic-layer etching (ALE) of TiN-by using a plasma-assisted thermal-cyclic process with a 300-mm tool-was demonstrated. The process consists of exposure to a downstream CHF3/O2 plasma (for surface modification) followed by infrared irradiation for thermal desorption of the modified surface. Etched amount of TiN per cycle saturated at around 0.6 nm/cycle with respect to both radical-exposure time and infrared-irradiation time. To examine the reaction mechanism of the cyclic etching, the surfaces of TiN samples after CHF3/O2 plasma exposure were analyzed by in situ X-ray photoelectron spectroscopy (XPS). Self-limiting formation of the surface-modified layer, which was tentatively identified as an ammonium salt such as (NH4)xTiFy, was observed after radical exposure. It was confirmed by in situ XPS that the surface-modified layer was removed after thermal annealing at 110 °C. Isotropic ALE of TiN was thus demonstrated by using formation and desorption of ammonium salt in CHF3/O2 downstream plasma, which was also used for isotropic ALE of Si3N4.

DOI： 10.1088/1361-6463/ab3cf3

Simulation-aided design of very-high-frequency excited nitrogen plasma confinement using a shield plate 査読有り

Isobe, Y; Sakai, T; Suguro, K; Miyashita, N; Kondo, H; Ishikawa, K; Wilson, AF; Shimizu, N; Oda, O; Sekine, M; Hori, M

JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B 37 巻 ( 6 ) 2019年11月

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

Nitrogen atoms are versatile for nitridation applications and do not lead to plasma-induced damage. Large-sized wafer processing demands a uniform supply of nitrogen atoms produced in a high-density very-high-frequency excited plasma of N2 without ammonia. The confinement of plasma through the use of a plasma shield plate (PSP) allows the samples to be separated in a downstream chamber. Generation and transport of N atoms were computationally simulated, and the PSP designs were implemented by PSP parameterization. The supply of high-density N radicals to the sample stage was optimally designed with sufficiently small holes and thin PSP to satisfy an aspect ratio of thickness-to-hole-diameter of less than 2.5.

DOI： 10.1116/1.5114831

Oxidative stress-dependent and -independent death of glioblastoma cells induced by non-thermal plasma-exposed solutions 査読有り Open Access

Tanaka, H; Mizuno, M; Katsumata, Y; Ishikawa, K; Kondo, H; Hashizume, H; Okazaki, Y; Toyokuni, S; Nakamura, K; Yoshikawa, N; Kajiyama, H; Kikkawa, F; Hori, M

SCIENTIFIC REPORTS 9 巻 ( 1 ) 頁： 13657 2019年9月

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

Non-thermal atmospheric pressure plasma has been widely used for preclinical studies in areas such as wound healing, blood coagulation, and cancer therapy. We previously developed plasma-activated medium (PAM) and plasma-activated Ringer’s lactate solutions (PAL) for cancer treatments. Many in vitro and in vivo experiments demonstrated that both PAM and PAL exhibit anti-tumor effects in several types of cancer cells such as ovarian, gastric, and pancreatic cancer cells as well as glioblastoma cells. However, interestingly, PAM induces more intracellular reactive oxygen species in glioblastoma cells than PAL. To investigate the differences in intracellular molecular mechanisms of the effects of PAM and PAL in glioblastoma cells, we measured gene expression levels of antioxidant genes such as CAT, SOD2, and GPX1. Microarray and quantitative real-time PCR analyses revealed that PAM elevated stress-inducible genes that induce apoptosis such as GADD45α signaling molecules. PAL suppressed genes downstream of the survival and proliferation signaling network such as YAP/TEAD signaling molecules. These data reveal that PAM and PAL induce apoptosis in glioblastoma cells by different intracellular molecular mechanisms.

DOI： 10.1038/s41598-019-50136-w

Atmospheric Pressure Plasma-Treated Carbon Nanowalls' Surface-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (CNW-SALDI-MS) 査読有り

Ohta, T; Ito, H; Ishikawa, K; Kondo, H; Hiramatsu, M; Hori, M

C-JOURNAL OF CARBON RESEARCH 5 巻 ( 3 ) 2019年9月

Self-limiting reactions of ammonium salt in CHF<sub>3</sub>/O<sub>2</sub> downstream plasma for thermal-cyclic atomic layer etching of silicon nitride 査読有り

Shinoda, K; Miyoshi, N; Kobayashi, H; Izawa, M; Saeki, T; Ishikawa, K; Hori, M

JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A 37 巻 ( 5 ) 2019年9月

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

Self-limiting reactions of ammonium salt in CHF3/O2 downstream plasma were demonstrated for thermal-cyclic atomic layer etching (ALE) of Si3N4. In situ x-ray photoelectron spectroscopy analysis shows that an (NH4)2SiF6 by-product of the same thickness forms on Si3N4 in a wide gas composition range. The (NH4)2SiF6 layer prevents etching of Si3N4 during continuous plasma exposure in that wide range. The (NH4)2SiF6 layer was sublimated by heating, which was consistent with the result of the thermodynamic calculation. The reactions of the (NH4)2SiF6 layer in CHF3/O2 downstream plasma are used for thermal-cyclic ALE of Si3N4 with a newly developed 300-mm tool equipped with an in situ ellipsometer. It was confirmed that the amount etched per cycle saturates with respect to both plasma exposure time and infrared irradiation time.

DOI： 10.1116/1.5111663

Review of methods for the mitigation of plasma-induced damage to low-dielectric-constant interlayer dielectrics used for semiconductor logic device interconnects 査読有り

Miyajima, H; Ishikawa, K; Sekine, M; Hori, M

PLASMA PROCESSES AND POLYMERS 16 巻 ( 9 ) 2019年9月

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

The developments in advanced interconnect technology for semiconductor logic devices for the mitigation of plasma-induced damage to low-dielectric-constant (low-k) materials, including fluorosilicate glass and carbon-doped silicon oxide is reviewed. The chemical bond structures of low-k materials are summarized to help mitigate the k value degradation caused by moisture uptake after plasma processes. Damage suppression is accomplished by integrating deposition chemistries, pattern etch transfer, and post-etch cleaning technologies. On the basis of analyses results, a discussion on the bond engineering of low-k materials and their degradation during plasma processing is given. Challenges facing low-k interconnect technology are also addressed.

DOI： 10.1002/ppap.201900039

Simultaneous achievement of antimicrobial property and plant growth promotion using plasma-activated benzoic compound solution 査読有り

Iwata, N; Gamaleev, V; Hashizume, H; Oh, JS; Ohta, T; Ishikawa, K; Hori, M; Ito, M

PLASMA PROCESSES AND POLYMERS 16 巻 ( 8 ) 2019年8月

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

This study assesses a potential use of the recently developed nonthermal atmospheric pressure plasma technology in hydroponic plant cultivation. Two types of plasma-activated liquid solutions were compared, namely, l-Phenylalanine (l-Phe), which had a benzene ring structure, and l-Alanine (l-Ala), which did not have a benzene ring structure. Antimicrobial property and plant growth enhancement were simultaneously obtained when plasma-activated l-Phe was used. We found that the benzene ring structure in solution contributed to antimicrobial property. Further, colony forming unit assay indicated that 99% of Escherichia coli (E. coli) were eliminated after 24-h incubation and radish sprout growth increased by about 40% after 2 days of cultivation.

DOI： 10.1002/ppap.201900023

Gene Expression of Osteoblast-like Cells on Carbon-Nanowall as Scaffolds during Incubation with Electrical Stimulation 査読有り

Ichikawa T., Kondo H., Ishikawa K., Tsutsumi T., Tanaka H., Sekine M., Hori M.

ACS Applied Bio Materials 2 巻 ( 7 ) 頁： 2698 - 2702 2019年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ACS Applied Bio Materials

Nanostructured cell-culture scaffolds of carbon nanowalls (CNWs) were prepared by changing average wall-to-wall distances either 132 or 220 nm. Osteoblast-like cells (Saos-2) proliferated during 4 day incubation on the wider (220 nm) CNW scaffolds in the presence of electrical stimulation (ES). Differentiation gene expression levels of Runt-related transcription factor 2 (Runx2) and osteocalcin (OC) were suppressed after 10 day incubation, which indicated that the average wall-to-wall distances of the CNW scaffolds affect suppression of Runx2 and OC gene expression. This technique holds promise for controlling the differentiation of osteoblast-like cells.

DOI： 10.1021/acsabm.9b00178

Rethinking surface reactions in nanoscale dry processes toward atomic precision and beyond: a physics and chemistry perspective 査読有り国際共著 Open Access

Ishikawa, K; Ishijima, T; Shirafuji, T; Armini, S; Despiau-Pujo, E; Gottscho, RA; Kanarik, KJ; Leusink, GJ; Marchack, N; Murayama, T; Morikawa, Y; Oehrlein, GS; Park, S; Hayashi, H; Kinoshita, K

JAPANESE JOURNAL OF APPLIED PHYSICS 58 巻 ( SE ) 2019年6月

担当区分：最終著者,　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 this review, we discuss the progress of emerging dry processes with atomic precision. Researchers in the field of plasma processing and surface science have addressed the increasingly challenging demands of material selectivity by utilization of synergistic enhancement of etching or deposition. The discussion encompasses major challenges in the plasma science and technology community. The focus of the review is advances in atomic layer etching and area-selective deposition with activation or deactivation, especially in terms of materials scaling and variety. Control of high-aspect-ratio feature fabrication in semiconductor manufacturing and etched shapes of interior features at the nanoscale are needed. Issues related to profile distortion have received much attention. State-of-the-art techniques used in semiconductor manufacturing are reviewed and future challenges are outlined.

DOI： 10.7567/1347-4065/ab163e

Plasma-activated solution alters the morphological dynamics of supported lipid bilayers observed by high-speed atomic force microscopy 査読有り

Yamaoka, S; Kondo, H; Hashizume, H; Ishikawa, K; Tanaka, H; Hori, M

APPLIED PHYSICS EXPRESS 12 巻 ( 6 ) 2019年6月

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 effects of plasma-activated Ringer's lactate solution (PAL) on supported lipid bilayers (SLBs) as a cell membrane model were investigated. PAL has selective killing effects on cancer cells. High-speed atomic force microscopy revealed alterations in the morphological dynamics of SLBs in PAL. SLB islands decreased approximately 20-fold faster in the presence of PAL compared to Ringer's lactate solution without plasma treatment. The effect of plasma treatment on the Ringer's lactate solution produced PAL components that account for the observed effects on cell membranes, such as removal of lipid molecules from the edges of SLBs and the following SLBs shrinkage.

DOI： 10.7567/1882-0786/ab1a58

Progress and perspectives in dry processes for emerging multidisciplinary applications: how can we improve our use of dry processes? 査読有り Open Access

Iwase, T; Kamaji, Y; Kang, SY; Koga, K; Kuboi, N; Nakamura, M; Negishi, N; Nozaki, T; Nunomura, S; Ogawa, D; Omura, M; Shimizu, T; Shinoda, K; Sonoda, Y; Suzuki, H; Takahashi, K; Tsutsumi, T; Yoshikawa, K; Ishijima, T; Ishikawa, K

JAPANESE JOURNAL OF APPLIED PHYSICS 58 巻 ( SE ) 2019年6月

担当区分：最終著者,　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 non-thermal nature of chemical reactions in plasma chemistry is considered to be suitable for next-generation energy production from plasma-material syntheses and renewable sources. As emerging multidisciplinary applications, plasma medicine and plasma agriculture are currently topical applications that make use of atmospheric pressure plasmas. Here, we conduct a systematic review of the literature over the last 40 years to evaluate the history and progress of dry processes with regard to atmospheric pressure plasma technologies as well as material synthesis and thin-film deposition. In this review, selected breakthroughs are reviewed. Finally, near-future major challenges are addressed to encourage new multidisciplinary research across the plasma science and technology community.

DOI： 10.7567/1347-4065/ab163a

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