Performance enhancement of InAlN/GaN HEMTs by KOH surface treatment

Superior electronic and thermal properties have made InAlN/GaN high-electron-mobility transistors (HEMTs) an attractive candidate for power electronics applications. However, their high gate leakage current remains a serious challenge affecting the reliability and performance of these heterostructures. Leakage paths through dislocations or by percolation through inhomogeneities in the InAlN alloy barrier restrict the voltage handling capability of these HEMTs. In this work, we show that surface treatment with KOH greatly reduces the gate leakage current. Consequently, the switching characteristics of the HEMTs improve, and they exhibit lower subthreshold slopes and improved breakdown characteristics. The finding should be of interest for both microwave and power electronics applications of nitride HEMTs. © 2014 The Japan Society of Applied Physics