ANALYTICAL MODEL FOR P-CHANNEL MOSFETS

Abstract

We described a new analytical model for p-channel MOSFET's. The model is based on the unified charge control model (UCCM) which allows us to describe both the subthreshold and the above threshold regimes using one continuous equation. The model is continuous from the linear to the saturation region of transistor operation. We also derive and incorporate into our model a new equation for the dependence of the hole mobility-mu on gate-to-source voltage (V(GS)) and threshold voltage (V(th0)). According to this relation, 1/mu is a linear function of (V(GS) + 2V(th0)). Our model allows us to propose a simple and unambiguous characterization procedure for extracting device parameters. We report detailed measurements of capacitance-voltage (C-V) and current-voltage (I-V) characteristics of p-channel MOSFET's with different gate lengths. The results of our calculations based on the parameters extracted from the measurement data are in excellent agreement with our experimental results. We conclude that our new model is ideally suited for applications in computer-aided design software for simulation of both digital and analog circuits, and for automated parameter extraction.