Exploitation of Hole Injection and Spreading for Dynamic Enhancement in p-GaN Gate HEMT under Room/High Temperatures

Abstract

In this study, we investigate the role of hole injection and spreading in a p-GaN gate HEMT for addressing buffer-related dynamic $R_{\text{ON}}$ degradations. The proposed structure includes a buried AlGaN layer that acts as a hole barrier and provides a hole spreading channel (BHSC) under the 2DEG channel. During the on-state, holes are injected from the gate and spread along the BHSC. We observe that the hole injection is enhanced with increasing temperatures. The lateral spreading of holes is critical for suppressing buffer trapping outside of the gate region. As the suppression of buffer trapping is enhanced with an increase in $V_{\text{GS}}$, the dynamic $R_{\text{ON}}$ is dramatically reduced. We then adopt the widely used back-gating test to evaluate the dynamic $R_{\text{ON}}$ when buffer trapping is intentionally introduced. Finally, we demonstrate that the proposed device with BHSC exhibits nearly zero buffer-related dynamic $R_{\text{ON}}$ degradation from room temperature to 125°C.