A computer-aided design model for high-voltage double diffused MOS (DMOS) transistors

High-voltage double diffused metal-oxide semiconductor transistors (DMOST's) have been fabricated with drain-source breakdown voltage greater than 200 V. This paper describes an experimental and theoretical study of the current-voltage behavior of these devices leading to a two-component MOS field effect transistor (MOSFET)-resistor model appropriate for computer-aided circuit design. The effects of velocity saturation, mobility reduction, and nonuniform impurity concentration in the channel, and of spreading resistance in the drift region are considered. Parameter extraction for experimentally characterizing these effects is described. Comparison of experimental and theoretical results shows that the model accurately predicts the device I/V characteristics. The range of validity of the model is limited primarily by high current saturation effects.