Dependence of ionization current on gate bias in GaAs MESFETs

Abstract
The nonmonotonic behavior of gate current Ig as a function of gate-to-source voltage Vgs is reported for depletion-mode double-implant GaAs MESFETs. Experiments and numerical simulations show that the main contribution to Ig (in the range of drain biases studied) comes from impact-ionization-generated holes collected at the gate electrode, and that the bell shape of the Ig(Vgs) curve is strongly related to the drop of the electric field in the channel of the device as Vgs is moved towards positive values