研究者詳細 - 石川　健治

論文 - 石川　健治

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Selective atomic-level etching using two heating procedures, infrared irradiation and ion bombardment, for next-generation semiconductor device manufacturing 査読有り

Shinoda, K; Miyoshi, N; Kobayashi, H; Miura, M; Kurihara, M; Maeda, K; Negishi, N; Sonoda, Y; Tanaka, M; Yasui, N; Izawa, M; Ishii, Y; Okuma, K; Saldana, T; Manos, J; Ishikawa, K; Hori, M

JOURNAL OF PHYSICS D-APPLIED PHYSICS 50 巻 ( 19 ) 2017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：Journal of Physics D: Applied Physics

The demand for precisely controlled etching is increasing as semiconductor device geometries continue to shrink. To fulfill this demand, cyclic atomic level/layer etching will become one of the key technologies in semiconductor device manufacturing at nanometer dimensions. This review describes recent trends in semiconductor devices and some of the latest results on cyclic atomic-level etching. In particular, it focuses on two types of cyclic etching that use different heating procedures: infrared irradiation for isotropic etching and Ar+ ion bombardment for anisotropic etching. It describes how an inductively-coupled-plasma down-flow etching apparatus with infrared lamps can be used for isotropic cyclic etching. The isotropic cyclic etching of SiN involves the formation and thermal desorption of ammonium hexafluorosilicate-based surface modified layers. This method features high selectivity with respect to SiO2, atomic-level control of the amount of SiN etching, and isotropic etched features. On the other hand, the anisotropic cyclic etching with Ar+ ion bombardment uses a microwave electron-cyclotron-resonance plasma etching apparatus. The anisotropic process for poly Si is composed of cyclic repetitions of chlorine adsorption and Ar+ ion bombardment. The anisotropic process for SiN is composed of cyclic repetitions involving an adsorption step using hydrofluorocarbon chemistry and a desorption step using Ar+ ion bombardment. Potential applications of these isotropic/anisotropic cyclic etching processes are described.

DOI： 10.1088/1361-6463/aa6874

Web of Science

Scopus

Spatial distributions of O, N, NO, OH and vacuum ultraviolet light along gas flow direction in an AC-excited atmospheric pressure Ar plasma jet generated in open air 査読有り

Takeda, K; Ishikawa, K; Tanaka, H; Sekine, M; Hori, M

JOURNAL OF PHYSICS D-APPLIED PHYSICS 50 巻 ( 19 ) 2017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：Journal of Physics D: Applied Physics

Ground-state O (3Pj) and N (4S°) atoms, nitric oxide (NO) and hydroxyl (OH) radicals, and vacuum ultraviolet (VUV) radiation emitted from an AC-excited Ar atmospheric pressure plasma jet (APPJ) operated in open air were measured using VUV absorption spectroscopy, laser induced fluorescence spectroscopy and optical emission spectroscopy, respectively. The O (3Pj) density decreased with increasing distance from the plasma head, and the decrease rate in the edge region of the plasma jet around 8 mm distance was especially high. On the other hand, the N (4S°) atom density was almost constant up to approximately 10 mm and increased with the distance over 12 mm. The relative NO density increased with the distance up to 10 mm and then became saturated, although the OH density was significantly reduced from the plasma jet exit of the head, and could be observed in the plasma jet only up to the distance of 5 mm. Emissions due to N, H and O atoms were observed in the VUV region and the emission intensity for N atoms (wavelength: 174.3 nm) decreased exponentially with increasing the distance. The results obtained with the Ar APPJ operated in open air conditions indicate the generation of many different reactive oxygen and nitrogen species by gas-phase reactions, and the composition of the reactive species is strongly dependent on the distance from the plasma head. These results are very useful for clarifying the kinetics of reactive species in APPJs and their application in various technological fields.

DOI： 10.1088/1361-6463/aa6555

Web of Science

Scopus

電子スピン共鳴法を活用したプラズマバイオ反応プロセスの診断招待有り査読有り

石川健治, 近藤隆, 竹田圭吾, 呉準席, 橋爪博司, 田中宏昌, 近藤博基, 太田貴之, 伊藤昌文, 関根誠, 堀勝

プラズマ核融合学会誌 2017年5月

Bactericidal pathway of Escherichia coli in buffered saline treated with oxygen radicals 査読有り

Kobayashi, T; Iwata, N; Oh, JS; Hahizume, H; Ohta, T; Takeda, K; Ishikawa, K; Hori, M; Ito, M

JOURNAL OF PHYSICS D-APPLIED PHYSICS 50 巻 ( 15 ) 2017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：Journal of Physics D: Applied Physics

Bactericidal effects of phosphate buffered saline treated with electrically neutral oxygen radicals on Escherichia coli (E. coli) are studied using an atmospheric pressure radical source and colony counting method. To clarify the bactericidal mechanism, the chemistry in phosphate buffers treated with oxygen radicals with and without saline has been quantitatively investigated using the well-established chemical reporters N,N-diethyl-p-phenylenediamine reagent and Amplex Red for residual chlorine (HClO and ClO-) and hydrogen peroxide (H2O2), respectively. From the results, we have found that the presence of chlorine in the solutions treated with oxygen radicals is the most important factor in the further chemical reactions to generate hypochlorous acid in E. coli death, and H2O2 is also linked to the bactericidal effect via an indirect chemical pathway.

DOI： 10.1088/1361-6463/aa61d7

Web of Science

Scopus

Effects of •OH and •NO radicals in the aqueous phase on H2O2 and NO2- generated in plasma-activated medium 査読有り

Kurake, N; Tanaka, H; Ishikawa, K; Takeda, K; Hashizume, H; Nakamura, K; Kajiyama, H; Kondo, T; Kikkawa, F; Mizuno, M; Hori, M

JOURNAL OF PHYSICS D-APPLIED PHYSICS 50 巻 ( 15 ) 2017年3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

A plasma-activated medium (PAM), which means a cell-culture medium irradiated with cold atmospheric plasmas or non-equilibrium atmospheric pressure plasma (NEAPP), has shown strong antitumor effects on various kinds of cells such as gastric cancer cells, human lung adenocarcinoma cells, human breast cancer cells and so on. In order to clarify the mechanism, it is extremely important to investigate the behaviors of stable and unstable reactive oxygen nitrogen species in culture medium irradiated by NEAPP. The roles of hydroxyl radicals (•OH) and nitric oxide (•NO) were studied to understand the dominant synthetic pathways of H2O2 and in culture medium irradiated with NEAPP. In the PAM, •OH in the aqueous phase was generated predominantly by photo-dissociation. However, most of the H2O2 nor generated in the PAM did not originate from aqueous •OH and •NO. Pathways for the generation of H2O2 and are suggested based on the high concentrations of intermediates generated at the gas/aqueous-phase interface following NEAPP irradiation. On the basis of these results, the reaction model of chemical species in the culture medium is proposed.

DOI： 10.1088/1361-6463/aa5f1d

Web of Science

Scopus

Spatial profiles of interelectrode electron density in direct current superposed dual-frequency capacitively coupled plasmas 査読有り

Ohya, Y; Ishikawa, K; Komuro, T; Yamaguchi, T; Takeda, K; Kondo, H; Sekine, M; Hori, M

JOURNAL OF PHYSICS D-APPLIED PHYSICS 50 巻 ( 15 ) 2017年3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

We present experimentally determined spatial profiles of the interelectrode electron density (n e) in dual-frequency capacitively coupled plasmas in which the negative direct current (dc) bias voltage (V dc) is superposed; in the experiment, 13 MHz (P low) was applied to the lower electrode and 60 MHz (P high) to the upper electrode. The bulk n e increased substantially with increases in the external power, P high, P low, and with increases in V dc. When P low was insufficient, the bulk n e decreased as the V dc bias increased. The bulk n e increased due to its dependence on V dc, especially for |V dc| > 500 V. This may correspond to the sheath voltages (V s) of the lower electrode. The n e values in front of the upper electrode were coupled with the V dc: the V dc dependence first decreased and then increased. The dc currents (I dc) of the upper electrode were collected when a large P low was applied. The value of I dc at the threshold value of V dc ≈ V s (e.g. -500 V) increased with an increase in n e. When |V dc| exceeded the threshold, the spatial n e profile and the I dc dependence were changed relative to the electrical characteristics of the dc superposition; this led to a change in the location of the maximum n e, the width of the area of n e depletion in front of the electrodes, and a transition in the electron heating modes.

DOI： 10.1088/1361-6463/aa60f7

Web of Science

Scopus

Behavior of absolute densities of atomic oxygen in the gas phase near an object surface in an AC-excited atmospheric pressure He plasma jet 査読有り

Takeda, K; Kumakura, T; Ishikawa, K; Tanaka, H; Sekine, M; Hori, M

APPLIED PHYSICS EXPRESS 10 巻 ( 3 ) 2017年3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 quantitative behavior of atomic oxygen in the gas phase near a Cu wire surface in an AC-excited atmospheric pressure He plasma jet in open air was measured using time-resolved vacuum ultraviolet absorption spectroscopy. The atomic oxygen density had a peak at a distance between the plasma source and the Cu wire, and the peak position moved away from the source with an increase in the gas flow rate. The behavior is considered to be dependent on the plasma density and the influence of ambient air. The results are important for supplying atomic oxygen to samples for plasma jet treatment in the atmosphere.

DOI： 10.7567/APEX.10.036201

Web of Science

Scopus

Characteristics of optical emissions of arc plasma processing for high-rate synthesis of highly crystalline single-walled carbon nanotubes 査読有り

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

JAPANESE JOURNAL OF APPLIED PHYSICS 56 巻 ( 3 ) 2017年3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：Japanese Journal of Applied Physics

Single-walled carbon nanotubes (SWNTs) were synthesized with a high growth rate using an arc plasma employing carbon electrodes with a Ni-Y mixture catalyst. However, the mechanism of growth of highly crystalline SWNTs has not been clarified. Reactions between carbon and catalyst are considered to be one of the crucial factors in SWNT growth. Optical emission spectroscopy (OES) provides the information about the species in the plasma. C2, Ni, and Y emissions in the arc plasma at different currents were measured to investigate the relationship between active species in the arc plasma and the SWNTsynthesis. On the basis of OES results, it was found that the balance between catalytic metal atoms and C2 radical emissions indicated the crystallinity ratio of SWNTs in thin graphitic or amorphous carbon layers. These results are useful for controlling the growth of SWNTs employing arc plasmas.

DOI： 10.7567/JJAP.56.035101

Web of Science

Scopus

Investigation of effects of ion energies on both plasma-induced damage and surface morphologies and optimization of high-temperature Cl2 plasma etching of GaN 査読有り

Liu, ZC; Pan, JL; Asano, A; Ishikawa, K; Takeda, K; Kondo, H; Oda, O; Sekine, M; Hori, M

JAPANESE JOURNAL OF APPLIED PHYSICS 56 巻 ( 2 ) 2017年2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：Japanese Journal of Applied Physics

The minimization of plasma-induced damage (PID) in plasma etching is important for the precise and smooth removal of a depth of approximately 7 nm of GaN films to fabricate gate-recess GaN-based normally-off power electronic devices. We have systematically studied the photoluminescence (PL) properties and surface morphologies of GaN films exposed to Cl2 plasma at 400°C, focusing on their dependences on etch time and ion energy. It is noticeable that PL degradation saturated at etch times of more than 2 min, while surface roughness increased continuously with etch time. Variations of surface roughness with bias voltage were negligible. PID was successfully suppressed by reducing bias voltage, leading to the decrease in incident ion energy on the surface, and thus the near-band-edge emission (NBE) intensity as a PL property was increased to 98.8% of the initial value.

DOI： 10.7567/JJAP.56.026502

Web of Science

Scopus

Absolute density of precursor SiH3 radicals and H atoms in H2-diluted SiH4 gas plasma for deposition of microcrystalline silicon films 査読有り

Abe, Y; Ishikawa, K; Takeda, K; Tsutsumi, T; Fukushima, A; Kondo, H; Sekine, M; Hori, M

APPLIED PHYSICS LETTERS 110 巻 ( 4 ) 2017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：Applied Physics Letters

Microcrystalline hydrogenated silicon films were produced at a high deposition rate of about 2 nm/s by using a capacitively coupled plasma under a practical pressure of around 1 kPa. The SiH4 source gas was almost fully dissociated when highly diluted with H2 gas, and the dominant species in the gas phase were found to be SiH3 radicals, which are film-growth precursors, and H atoms. The absolute density of these species was measured as the partial pressure of SiH4 gas was varied. With the increasing SiH4 gas flow rate, the SiH3 radical density, which was on the order of 1012 cm-3, increased linearly, while the H-atom density remained constant at about 1012 cm-3. The film growth mechanism was described in terms of precursors, based on the measured flux of SiH3 radicals and H atoms, and the relative fraction of higher-order radicals.

DOI： 10.1063/1.4974821

Web of Science

Scopus

Microfluidic transport through micro-sized holes treated by non-equilibrium atmospheric-pressure plasma 査読有り Open Access

Takumi Ito, Kenji Ishikawa, Daisuke Onoshima, Naoto Kihara, Kentaro Tatsukoshi, Hidefumi Odaka, Hiroshi Hashizume, Hiromasa Tanaka, Hiroshi Yukawa, Keigo Takeda, Hiroki Kondo, Makoto Sekine, Yoshinobu Baba, and Masaru Hori

IEEE Transactions on Plasma Science 44 巻 ( 12 ) 頁： 3060 - 3065 2016年12月

Non-thermal atmospheric pressure plasma activates lactate in Ringer’s solution for anti-tumor effects 査読有り Open Access

Hiromasa Tanaka, Kae Nakamura, Masaaki Mizuno, Kenji Ishikawa, Keigo Takeda, Hiroaki Kajiyama, Fumi Utsumi, Fumitaka Kikkawa, and Masaru Hori

Scientific Reports 6 巻頁： 36282 2016年11月

Effects of assisted magnetic field to an atmospheric-pressure plasma jet on radical generation at the plasma-surface interface and bactericidal function 査読有り

Chih-Tung Liu, Takumi Kumakura, Kenji Ishikawa, Hiroshi Hashizume, Keigo Takeda, Masafumi Ito, Jong-Shinn Wu, and Masaru Hori

Plasma Sources Science and Technology 25 巻 ( 6 ) 頁： 065005 2016年10月

Micro sand timer in glass membrane device separates single circulating tumor cells in blood 査読有り

Daiki Kuboyama, Daisuke Onoshima, Hiroshi Yukawa, Hiromasa Tanaka, Kenji Ishikawa, Masaru Hori, and Yoshinobu Baba

The 20th International Conference on Miniaturized Systems for Chemistry and Life Sciences, Micro Total Analysis Systems 2016 (Convention Center Dublin, Dublin, Ireland, Oct. 9-13, 2016) 頁： 297 - 298 2016年10月

Control of Internal Plasma Parameters Toward Atomic Level Processing 査読有り

Makoto Sekine, Takayoshi Tsutsumi, Yusuke Fukunaga, Keigo Takeda, Hiroki Kondoa, Kenji Ishikawa, and Masaru Hori

ECS Transactions 75 巻 ( 6 ) 頁： 21 - 24 2016年10月

Thermal cyclic etching of silicon nitride by formation and desorption of ammonium fluorosilicate 査読有り

Kazunori Shinoda, Masaru Izawa, Tadamitsu Kanekiyo, Kenji Ishikawa, and Masaru Hori

Applied Physics Express 9 巻 ( 10 ) 頁： 106201 2016年9月

Cold plasma interactions with enzymes in foods and model systems 査読有り国際共著

N. N. Misra, S. K. Pankaj, Annalisa Segat, and Kenji Ishikawa

Trends in Food Science & Technology 55 巻頁： 39 - 47 2016年9月

Synthesis of calcium oxalate crystals in culture medium irradiated with non-equilibrium atmospheric-pressure plasma 査読有り

Naoyuki Kurake, Hiromasa Tanaka, Kenji Ishikawa, Kae Nakamura, Hiroaki Kajiyama, Fumitaka Kikkawa, Masaaki Mizuno, Yoko Yamanishi, and Masaru Hori

Applied Physics Express 9 巻 ( 9 ) 頁： 096201 2016年8月

Rapid electron density decay observed by surface-wave probe in afterglow of pulsed fluorocarbon-based plasma 査読有り

Yoshinobu Ohya, Manabu Iwata, Kenji Ishikawa, Makoto Sekine, Masaru Hori, and Hideo Sugai

Japanese Journal of Applied Physics 55 巻 ( 8 ) 頁： 080309 2016年7月

ラジカル支援原子層制御ナノプロセス招待有り査読有り

石川健治, 小林明子, 盧翌, 竹田圭吾, 近藤博基, 関根誠, 堀勝

化学工学 2016年7月

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