[1] National Institute of Advanced Industrial Science and Technology (AIST), Device Technology Research Institute, 1-2-1 Namiki, Tsukuba, Ibaraki,305-8564, Japan
[2] National Institute of Advanced Industrial Science and Technology (AIST), Advanced Power Electronics Research Center (ADPERC), 1-8-31 Midoriokai, Ikeda, Osaka,563-8577, Japan