1. The Oarai Center, Institute for Materials Research, Tohoku University, 2145-2 Narita, Oarai, Ibaraki 311-1313, Japan
2. Department of Electrical Engineering, Faculty of Engineering, Tokyo City University, 1-28-1 Tamazutsumi, Setagaya-ku, Tokyo 158-8557, Japan
3. Renesas Semiconductor Manufacturing Co., Ltd., 1120 Shimokuzawa, Sagamihara, Kanagawa 252-5298, Japan
4. Renesas Electronics Corporation, 751 Horiguchi, Hitachinaka, Ibaraki 312-8504, Japan