1. Anhui Province Key Laboratory of Simulation and Design for Electronic Information System, Hefei Normal University, Hefei, Anhui 230601, P. R. China
2. Industry-Education-Research Institute of Advanced Materials and Technology for Integrated Circuits, School of Electronics and Information Engineering, Anhui University, Hefei, Anhui 230601, P. R. China
3. School of Microelectronics, Hefei University of Technology, Hefei, Anhui 230009, P. R. China