On the α-particle irradiation effects in MESFETs

α-particle irradiation investigations have been carried out on various structure GaAs metal-semiconductor field-effect transistors. The device characteristics were measured before irradiation and after α-particle irradiation with fluences ranging from 5×1010 to 3×1012 cm-2. The carrier removal rate was found to be independent of the doping level as determined from Schottky diodes and device parameters. Five traps were found to be introduced by irradiation. Two of them were found to determine the temperature dependence of drain current. The threshold voltage shift was modeled taking into account the degradation of the channel carrier removal, the gate barrier height and the channel-substrate space charge region width