Gunn domain formation in the saturated current region of GaAs MESFETs

A semi-empirical model is proposed to describe the behavior of a 1 µm gate GaAs MESFET in the saturated current region. It divides the MESFET into three sections: an "ideal" gradual channel portion (1); an adjacent stationary Gunn domain region extending to the drain (2); and a leakage path shunting these two portions at high drain bias via the non-ideal interface and substrate (3). In portion (1), a pinchoff potential for an ideally abrupt interface is defined. Properties of portions (2) and (3) are inferred from the implications of the gradual channel approximation for portion (1) and the experimental data.