Effects of indium within a barrier on the gate leakage current in an InAlGaN/GaN high-electron-mobility transistor

Abstract We investigated the impact of In within barriers on the gate leakage current in InAlGaN/GaN high-electron-mobility transistors (HEMTs). The results revealed that the gate leakage current in the (In)AlGaN barriers depends solely on the two-dimensional electron gas density, regardless of the presence of In atoms. Furthermore, the inclusion of In atoms reduces tensile strain within the high-Al-composition barrier, suppressing crack formation. This makes InAlGaN suitable for high-output-power HEMTs with high-Al-content barriers. Moreover, we demonstrate that the terminating dislocations using an AlN spacer and an amorphous AlN cap are an effective method for suppressing the gate leakage current in InAlGaN/GaN HEMTs.