Suppression of Hot-Electron-Induced Dynamic RON Degradation in p-GaN Gate HEMT Using Active Passivation and Virtual Body

The dynamic R-ON performance of GaN power devices is reported to degrade after hot-electron stress, due to the generation of new traps. In this study, the p-GaN gate HEMTs with active passivation and virtual body (AP/VB-HEMTs) are proposed to address hot-electron induced dynamic degradation. The active passivation is a thinned p-GaN layer that extends from the gate towards the drain. The virtual body is a hole channel above a buried AlGaN layer, and is formed by holes injected from gate. As a result, the surface trapping caused by pre-existing and hot-electron generated traps are screened by the active passivation. The buffer traps are suppressed by the mobile holes in virtual body. To evaluate the effectiveness on suppressing hot-electron induced dynamic R-ON degradation, the devices are evaluated after hot-electron stress with different stress time and stress current. After a 30-min hot-electron stress, the AP/VB-HEMT shows negligible dynamic R-ON increase, presenting a contrast to the severe degradation in conventional p-GaN gate HEMT, suggesting the enhanced suppressions against hot-electron stress in the AP/VB-HEMT.