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 I
g
versus V
ds
, 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.