Effect of Post-Gate Deposition Annealing on the Electrical Characteristics of AlGaN/GaN HEMTs with p-GaN Gate

Aiming towards fail-safe normally-off operation we have fabricated AlGaN/GaN HEMTs with p-GaN gate. From device transfer characteristics, we have confirmed that threshold voltage (Vth) was shifted towards the positive direction with increasing p-GaN layer thickness and this amount of shift was further enhanced by post-gate deposition annealing.