MOS Transistor Model

Application ID: 690

The MOSFET (Metal Oxide Semiconductor Field-Effect Transistor) is by far the most common semiconductor device, and the primary building block in all commercial processors, memories, and digital integrated circuits. During the past decades this device has experienced tremendous development, and today it is being manufactured with feature sizes of 90 nm and smaller.

This model calculates the DC characteristics of a MOS transistor using standard semiconductor physics. In normal operation, a system turns on a MOS transistor by applying a voltage to the gate electrode. When the voltage on the drain increases, the drain current also increases until it reaches saturation. The saturation current depends on the gate voltage.

This is a good example on how the solver scripting can be used, and also shows a technique to calculate initial guesses for nonlinear problem (especially for semiconductors). The model first calculates the initial guess, and then ramps the voltage on two terminals to reach a final value. The final sweep gives an example of an electrical characteristic of the MOS transistor called a drain diagram.

This application was built using the following: