1. Institute of MicroelectronicsPeking University Beijing 100871 China
2. National Key Laboratory of Science and Technology on Micro/Nano Fabrication Beijing 100871 China
3. Key Laboratory of Microelectronic Device and Integrated Technology Institute of Microelectronics Chinese Academy of Sciences Beijing 100029 China
4. Innovation Center for Microelectronics and Integrated SystemPeking University Beijing 100871 China