Systematic approach to modelling and parameter extraction of an ion-implanted GaAs MESFET

The authors have modelled current/voltage characteristics of GaAs MESFETs built on ion-implanted substrates. It is shown that, for a physically acceptable model, some of the parameters should be voltage-dependent. This would account for the dopant nonuniformity in the channel and two-dimensional effects. For a very simple model, a minimum of five voltage-independent parameters was required (this number increased to six if large biases were considered). To validate the model, a procedure is proposed for parameter extraction under different bias and implant conditions