Institution: | a R&D Center, Technology Division, Mitsubishi Materials Silicon Corporation, 1-297 Kitabukuro-cho, Omiya, Saitama 330-0835, Japan b Faculty of Education, Shinshu University, Nishinagano, Nagano 380-0871, Japan c Faculty of Engineering, Shinshu University, Wakasato, Nagano 380-0922, Japan |