Fundamental failure mechanisms limiting maximum voltage operation in AlGaN/GaN HEMTs

The authors report on the fundamental failure mechanisms limiting maximum applied voltage in AlGaN/GaN HEMTs. Device failure in high voltage off state conditions was studied by controlling drain leakage current and maximum applied drain voltage simultaneously. It was found that failure was associated with loss in gate control of channel current and a permanent degradation of gate diode leakage current. No permanent significant change until device failure was observed in ON-state parameters such as R_on, I_dss and I_dmax, thus distinguishing this failure mode from the inverse pieozo-electric effect as reported in literature.