GaAs MESFET simulation using PISCES with field-dependent mobility-diffusivity relation

Most conventional semiconductor device simulators, such as PISCES and BAMBI, use a constant diffusivity-to-mobility ratio modeling (linear relation). We modify PISCES to perform field-dependent diffusivity-to-mobility ratio (nonlinear relation) GaAs MESFET simulation and compare it to the constant ratio linear modeling. The results show that current overshoot and stable Gunn-domain formation occurred at a lower channel-impurity concentration for the field-dependent diffusivity-to-mobility ratio case. The transconductance and threshold voltage of a 1-µm gate-length MESFET are compared also.