SURFACE POTENTIAL DISTRIBUTION MODEL BASED ON ANALYTICAL CHANNEL POTENTIAL APPROXIMATION FOR ULTRA-THIN BODY POLY-SI THIN FILM TRANSISTORS IN LINEAR REGION

Abstract

For ultra-thin body polycrystalline silicon thin film transistors, the surface potential distribution model, in the linear region, based on the analytical channel potential (CP) approximation is presented without or with the interface charge, respectively. For the purpose of simplifying the process of the solution and with the merit of the clear physical picture, both the surface potential distribution models in the linear region are developed, attributed to the deduction of the analytical CP approximation, by solving one-dimensional Poisson’s equation and applying the Gauss’s law at the poly-Si/oxide interface. Furthermore, the quantitative conditions for the model validity are also developed for both surface potential distribution models. Under these proposed quantitative conditions, both models are verified by the two-dimensional-device simulation on the normalized channel distance under various gate voltages, drain voltages, channel lengths and various areal interface charge densities for the consideration of the interface charge.