1. State Key Lab of Fabrication Technologies for Integrated Circuits Institute of Microelectronics Chinese Academy of Sciences Beijing 100029 China
2. School of Microelectronics University of Science and Technology of China Hefei 230026 China
3. Beijing National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of Sciences Beijing 100190 China
4. University of Chinese Academy of Sciences Beijing 101408 China
5. Songshan Lake Materials Laboratory Dongguan 523808 China
6. Department of Electrical and Electronic Engineering The University of Hong Kong Pok Fu Lam Road Lung Fu Shan 999077 Hong Kong
7. Institute of Advanced Materials Beijing Normal University Beijing 100875 China