Reliability Analysis of Enhancement-Mode GaN MIS-HEMT with Gate-Recess Structure for Power Supplies

In this work, the reliability of enhancement-mode GaN MIS-HEMTs with gate-recess structure was investigated. Stress test under the positive gate bias was mainly considered. By the positive gate bias stress, R-on and V-p was varied. This shift was reversible. The deep-level optical spectroscopy (DLOS) suggested deep levels at the gate recessed region. These results lead to the conclusion that Ron and Vp shift was attributed by the deep level at the gate recessed region. By controlling the trap density at recessed region, we can suppress the R-on and V-p shift.