Enhancement-mode AlGaN/GaN MIS-HEMTs with low threshold voltage hysteresis using damage-free neutral beam etched gate recess

An enhancement-mode AlGaN/GaN MIS-HEMTs with low threshold voltage hysteresis using damage-free neutral beam etched (NBE) gate recess is reported. The NBE can eliminate the plasma-induced defects that generated by irradiating UV/VUV photons as encounted in the conventional inductively coupled plasma-reactive-ion etching (ICP-RIE). Combining the new gate recess process and PEALD-AlN interfacial passivation layer, the Al₂O₃/AlGaN/GaN enhancement-mode HEMT device shows a threshold voltage of 1.5 V and a current density of 449 mA/mm, and the three-terminal breakdown voltage was 432 V. The device also shows small hysteresis in threshold voltage at stable I-V curve.