Two-dimensional hot-electron models for short-gate-length GaAs MESFET's

Abstract

A detailed hot-electron device model suitable for modeling short-gate-length GaAs MESFET's is described. A two-dimensional numerical simulation is used to solve a set of semiclassical carrier transport equations, including a full rigorous solution of the energy conservation equation. The importance of the hot-electron effects is demonstrated and in particular the role of the electron temperature gradient in addition to velocity overshoot is emphasized. The influence of doping and mobility profiles are investigated and found to have a very significant effect on the device characteristics. The model is applied to a range of submicrometer-gate-length devices and is shown to be useful for characterizing devices with gate lengths down to less than 0.1 µm. The dependence of saturated drain current on gate length is quantified.