[1] Chinese Acad Sci, Inst Microelect, Key Lab Microelect Devices & Integrated Technol, Beijing 100029, Peoples R China
[2] Univ Chinese Acad Sci, Beijing 100049, Peoples R China
[3] Univ Sci & Technol China, Sch Microelect, Hefei 230026, Anhui, Peoples R China
[4] Univ Hong Kong, Dept Elect & Elect Engn, Pok Fu Lam Rd, Hong Kong, Peoples R China
[5] Univ Massachusetts, Dept Elect & Comp Engn, Amherst, MA 01003 USA