Identification of local gate leakage with electroluminescence using AlGaN/GaN HEMTS

An application for a transparent gate electrode with surface-side electroluminescence (EL) observation is proposed for identification of the gate leakage path in AlGaN/GaN high electron mobility transistors. This technique enables surface-side EL observation throughout the gate electrode, so that the substrate material is unrestricted. Through the transparent gate, a non-uniformly located spot-shape EL was clearly observed. By comparing devices with different leakage currents using EL intensity, the location marked by the spot-shape EL is found and demonstrates a dominant leakage path.