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Akishima, Japan

Ohachi T.,Doshisha University | Yamabe N.,Doshisha University | Yamamoto Y.,Doshisha University | Wada M.,Doshisha University | Ariyada O.,Arios Inc.
Journal of Crystal Growth | Year: 2011

A new spiral parallel mesh electrode (PME) is presented to control active nitrogen species in plasma-assisted molecular beam epitaxial (PA-MBE) growth of group III nitrides and their alloys. Direct flux of active nitrogen from radio frequency inductive coupled plasma (rf-ICP) discharge was able to be measured using a mesh electrode for filtering charge particles and electron emission due to the self-ionization of nitrogen atoms on a negatively biased electrode. In situ measurement of direct nitrogen atom fluxes using the spiral PME during PA-MBE growth of GaN and AlN on Si substrates is investigated. A linear rf power dependence of direct flux of active species on atoms such as nitrogen (NN), where N and N were ground and excited atoms, respectively, from a rf-ICP was confirmed by the spiral PME. An indirect flux of nitrogen adsorbed (ADS) atoms (NN) during discharge was also monitored by the spiral PME and received influence of the wall surface of the growth chamber. ADS nitrogen atoms are able to be used for nitridation of Si surface to grow a double buffer layer (DBL) AlN/β-Si3N4/Si. © 2010 Elsevier B.V. All rights reserved. Source


Ding W.,Saitama Institute of Technology | Ding W.,Dalian Jiaotong University | Guo Y.,Saitama Institute of Technology | Guo Y.,University Of Science And Technology Liaoning | And 4 more authors.
Modern Physics Letters B | Year: 2016

The surface of high density polyethylene (HDPE) substrate was bombarded by the CHx group ion beam, which was generated by the mixture of CH4/H2. Varying the CH4/H2 ratio, HDPE surfaces with different chemical bond structures and properties were obtained. Raman and XPS results show that sp2 and sp3 bond structures are formed at HDPE surface bombarded by CHx group ions. The sp3 bond fraction at bombarded HDPE surface depends on the H2 ratio in CH4/H2 mixture, because the H ion/atom/molecule can improve the growth of sp3 bond structure. For HDPE surface bombarded by CH4/H2 = 50/50, sp3 bond fraction reaches the maximum of 30.5%, the surface roughness decreases to 17.04 nm, and the static contact angle of polar H2O molecule increased to 140.2°. © 2016 World Scientific Publishing Company. Source


Narushima T.,Sugo Co. | Narushima T.,Hokkaido University | Yoshioka T.,Sugo Co. | Miyazaki H.,Sugo Co. | And 3 more authors.
Nippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals | Year: 2012

Non-oxidized metallic copper particles were prepared by plasma irradiation into aqueous solution of cupric sulfate in the presence of gelatin as a protective agent using home-made microwave induced plasma equipment. Then, two different steric structures of ascorbic acid, L-ascorbic acid and isoascorbic acid, were added as reducing auxiliaries. In the case of isoascorbic acid addition, metallic copper particles were obtained by plasma irradiation within about 5 minute. This result suggests that the reduction of copper ion from Cu 2+ to metallic Cu can be succeeded by hydrogen radical generated by plasma in water combination with isoascorbic acid, and without toxic chemical agent such as hydrazine. Additionally, the diameter of copper particles can be controlled by the mount of CuSO 4 · 5H 2O and gelatin. These results were indicated that the plasma in liquid process has possibilities for high-speed and low environmental load process to prepare metallic copper particles. © 2012 The Japan Institute of Metals. Source


Ohachi T.,Doshisha University | Yamabe N.,Doshisha University | Wada M.,Doshisha University | Ariyada O.,Arios Inc.
Japanese Journal of Applied Physics | Year: 2011

A radio frequency inductively coupled plasma (rf-ICP) nitrogen discharge was investigated to improve group III nitride growth on Si substrates. Two modes of the rf-ICP discharge, low brightness (LB) and high brightness (HB) discharges, were successfully controlled through mode transition. Direct irradiation and indirect irradiation of nitrogen atoms were applied for the growth of group III nitrides. As an application of indirect irradiation of nitrogen atoms, the growth of β-Si3N4 using interface reaction epitaxy (IRE) was studied. As applications of direct irradiation of nitrogen atoms, activity modulation migration-enhanced epitaxy (AM-MEE) and plasma-assisted molecular beam epitaxy (PA-MBE), which are atomic layer epitaxy (ALE) methods, are demonstrated. These growth systems operate to realize a single-growth process from a Si substrate to an AlN or GaN epitaxial layer, i.e., through preparation of a double buffer (DBL) layer of AlN/β-Si 3N4/Si after the growth of IRE β-Si3N 3 and IRE AlN. The electron emission due to the self-ionization of nitrogen atoms on a negatively biased electrode is demonstrated to measure in situ direct and indirect nitrogen atom fluxes during the growth. © 2011 The Japan Society of Applied Physics. Source


Patent
Arios Inc. and The Doshisha | Date: 2013-01-03

An atomic flux measurement device for measuring the amount of dissociated atomic flux produced by discharge and emitted from a plasma generation cell into a vacuum camber. The atomic flux measurement device includes a counter electrode body including a pair of first and second sheet-like electrodes that are arranged substantially parallel to each other with a predetermined spacing between them, a direct-current power supply configured to maintain the first sheet-like electrode at a negative potential so that atoms attached to the inner surface of the sheet-like electrode undergo self-ionization and to apply a direct-current voltage between the first and second sheet-like electrodes so that a current flows between the first and second sheet-like electrodes, and a direct-current ammeter configured to measure a current flowing due to electrons emitted by the self-ionization of the dissociated atoms attached to the inner surface of the first sheet-like electrode.

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