Two-dimensional models of threshold voltage and subthreshold current for symmetrical double-material double-gate strained Si MOSFETs**Project supported by the National Natural Science Foundation of China (Grant Nos. 61376099, 11235008, and 61205003).

Abstract

The two-dimensional models for symmetrical double-material double-gate (DM-DG) strained Si (s-Si) metal–oxide semiconductor field effect transistors (MOSFETs) are presented. The surface potential and the surface electric field expressions have been obtained by solving Poisson’s equation. The models of threshold voltage and subthreshold current are obtained based on the surface potential expression. The surface potential and the surface electric field are compared with those of single-material double-gate (SM-DG) MOSFETs. The effects of different device parameters on the threshold voltage and the subthreshold current are demonstrated. The analytical models give deep insight into the device parameters design. The analytical results obtained from the proposed models show good matching with the simulation results using DESSIS.