Low thermal budget V/Al/Mo/Au ohmic contacts for improved performance of AlGaN/GaN MIS-HEMTs

Abstract

Abstract We report on the highly improved performance of Al2O3/AlGaN/GaN MIS-HEMTs using a V/Al/Mo/Au metal stack as ohmic electrodes. Transfer length method test structures using a V/Al/Mo/Au metal stack annealed at a temperature of 660 °C revealed highly linear current–voltage curves and smooth surface morphology. Compared with reference MIS-HEMTs using Ti/Al/Mo/Au annealed at the standard rapid thermal annealing temperature of 880 °C, V-based devices exhibited less hysteresis of transfer curves and showed higher gate controllability of the drain current, suggesting a highly improved Al2O3/AlGaN interface. Measurements and analyses of capacitance–voltage characteristics of corresponding MIS-capacitors corroborated these findings. The V-based ohmic contact could open new avenues towards enhanced GaN-based MIS-HEMTs performance.