1. Proc. 4th Conf. Solid State Devices;Warabisako,1973
2. Proc. 10th Conf. Solid State Devices;Wada,1979
3. IEEE Int. Solid State Circuits Conference;Furuyama,1986
4. Symp. VLSI Technology;Kinugawa,1985
5. Extended Abstract of 17th Conf. Solid State Devices and Materials;Natsuaki,1895