Two-dimensional particle modeling of submicrometer gate GaAs FET´s near pinchoff

The characteristics of very short gate GaAs MESFET´s have been studied using a particle model which takes into account the hot-electron transport phenomena, i.e., the velocity overshoot. A brief description of this model is given. A particular emphasis has been placed on the pinched ranges of operation, showing an exponential dependence of Igversus Vds, and on the transition between the pinched and the saturated ranges, in which the trapped domain controls the channel. Analytical derivations are included leading to some scaling-down considerations.