Mechanism Analysis of Gate Leakage Current Degradation of GaAs MESFETs

Forward and Reverse Gate-Grain Leakage Current of GaAs MESFETs increase after High Temperature Storage Test (HTST) .In order to study the failure mechanisms an experiment to measure the low-biased forward current of Gate-Grain diode as a function of temperature has been carried out.The change of density of Combination-Generation Centers(C-G C)after HTST has been estimated qualitatively. The increase of the both leakage currents is due to the increase of C-G C in the active layer under the gate An evidence of gate metal sinking and metal-semiconducion after HTST has been obtained.