Effect of High-Temperature Annealed Al2O3 insulator on GaN MIS-HEMTs performance

We investigated the effects of high-temperature annealed (HTA) at 880 °C of Al2O3 gate insulator on the performance of AlGaN/GaN MIS-HEMTs. HTA-Al2O3 MIS-capacitors exhibited evidences of spillover of 2DEG from AlGaN/GaN to Al2O3/AlGaN interface. Moreover, HTA-Al2O3 MIS-HEMTs also showed smaller hysteresis in transfer curves and higher maximum drain current compared to those of the reference Al2O3/AlGaN/GaN MIS-HEMTs. These suggest highly improved insulator/semiconductor interfaces by high-temperature annealing of Al2O3 insulator layer.