Neutral beam process in AlGaN/GaN HEMTs: Impact on current collapse

In this paper, we report a promising approach for the gate recess process with a suppressed current collapse in GaN-based high electron mobility transistors (HEMTs) by means of neutral beam (NB). A recessed gate structure has been widely studied as a way to realize normally-off operation in GaN, InP, and GaAs-based HEMTs. Since GaN-based materials are usually etched by dry process, plasma-induced damage is a serious concern. NB is free from electrical charges and UV photons, resulting in an accurate control of etching depth and less plasma-induced damages. In this work, we introduce NB irradiation to the gate interface and measured DC and gate-pulsed output characteristics. The results suggest that NB is applicable for the gate recess etching with suppressing the current collapse.