A calibrated model for the subthreshold operation of a short channel MOSFET including surface states

Describes a simple two-dimensional subthreshold model for short channel MOSFET´s. The effects of surface state density are also included in the model. A regional charge density approximation was used in the solution of Poisson´s equation and an analytical solution of the continuity equation in two dimensions was derived. Excessive computations are avoided in the present model; this was made possible by the use of a valid regional charge approximation. The model was experimentally verified by performing measurements on short channel devices. The model was calibrated from measurements on a long channel device which was present on the same silicon chip. Results are presented for the subthreshold leakage current as a function of substrate bias, polysilicon gate length, diffusion depth and surface state density.