A simple analytical threshold voltage model of nanoscale single-layer fully depleted strained-silicon-on-insulator MOSFETs

For the first time, a simple and accurate analytical model for the threshold voltage of nanoscale single-layer fully depleted strained-silicon-on-insulator MOSFETs is developed by solving the two-dimensional (2-D) Poisson equation. In the proposed model, the authors have considered several important parameters: 1) the effect of strain (in terms of equivalent Ge mole fraction); 2) short-channel effects; 3) strained-silicon thin-film doping; 4) strained-silicon thin-film thickness; and 5) gate work function and other device parameters. The accuracy of the proposed analytical model is verified by comparing the model results with the 2-D device simulations. It has been demonstrated that the proposed model correctly predicts a decrease in threshold voltage with increasing strain in the silicon thin film, i.e., with increasing equivalent Ge concentration. The proposed compact model can be easily implemented in a circuit simulator