Proton-irradiation Effects on Charge Trapping-related Instability of Normally-off AIGaN/GaN Recessed MISHFETs

초록

We investigated proton-irradiation effects on the charge trapping-related instability of normally-off AIGaN/GaN recessed MISHFETs. The reduction of drain current (I-D) by 57.3 % and the shift of threshold voltage (Vth) by 1.5 V were induced by 5 MeV proton irradiation with a total dose of 5 x 10(14) cm(-2). Short-term DC voltage stress tests were carried out before and after irradiation in order to investigate how temporary instability caused by the charge trapping could be affected by the proton irradiation. The increase in the interface trap density was probed by capture emission time (CET) map and conductance method, whereas the breakdown voltage was increased after proton irradiation. TCAD simulation using Silvaco Atlas showed the reduction of lateral electric field of gate edge at drain side after proton irradiation as well as the increase of lateral electric field in the access region where charge trapping mostly occurs. Radiation effect can worsen the device instability by increasing interface traps and electric field in the access region.

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