Dependence of ionization current on gate bias in GaAs MESFETs

The nonmonotonic behavior of gate current I/sub g/ as a function of gate-to-source voltage V/sub gs/ is reported for depletion-mode double-implant GaAs MESFETs. Experiments and numerical simulations show that the main contribution to I/sub g/ (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 I/sub g/(V/sub gs/) curve is strongly related to the drop of the electric field in the channel of the device as V/sub gs/ is moved towards positive values.<
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