1. Graduate School of Science and Technology, Niigata University, Niigata 950-2181, Japan
2. Department of Electrical Engineering and Electronics, Kyushu Institute of Technology, Kitakyushyu 804-8550, Japan
3. Philtech Inc., Bunkyo, Tokyo 113-0033, Japan
4. GlobalWafers Japan Co., Ltd., Seiro, Niigata 957-0197, Japan
5. Toshiba Corporation, Yokohama 225-8522, Japan