1. Integrated Circuit Advanced Process Center, Institute of Microelectronics of Chinese Academy of Sciences, No. 3, Bei-Tu-Cheng West Road, Beijing 100029, China
2. Integrated Circuit Advanced Process Center, Institute of Microelectronics of Chinese Academy of Sciences, No. 3, Bei-Tu-Cheng West Road, Beijing 100029, China and School of Microelectronics, University of Chinese Academy of Sciences, No. 19(A), Yuquan Road, Beijing 100049, China