An IGFET inversion charge model for VLSI systems

Abstract

This paper describes a new analytical model for inversion and depletion charge that is valid in all regions of operation. The model is physical and includes the potential drop across the inversion layer. It therefore accounts for the flat portion of ordinary high-frequency <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C-V</tex> plots. It may also be used to derive compact expressions for two new terms, strong inversion threshold and intrinsic threshold, required to replace the single classical threshold term. The new terms allow expressions similar to the classical linear charge model and early weak inversion models to be applied to scaled devices, describing their operation in strong inversion and near cutoff.