Modeling the threshold voltage of long and short-channel fully depleted SOI MOSFETs with back gate substrate induced surface effects

A simple analytical threshold voltage models for long and short-channel fully depleted SOI MOSFETs have been derived. The models are based on the analytical solution of the potential distribution in the silicon film (front silicon), which is for the short-channel case is taken as the sum of the long-channel solution to the Poisson's equation and the short-channel solution to the Laplace equation, and the solution of the Poisson's equation in the silicon substrate (back silicon). The proposed models accounts for the effects of the back gate substrate induced surface potential (SISP) at the buried oxide-substrate interface. The models predications are in close agreement with PISCES simulation results.