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 R_on and V_p 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.