Electrical and Optical Characterization of a Normally-Off AlGaN/GaN HEMT With a Segmented-Extended p -GaN Gate Structure

A segmented-extended p-GaN (SEP) gate structure is proposed and implemented in a p-GaN/ AlGaN/GaN high-electron-mobility transistor (HEMT). Compared to conventional p-GaN HEMTs, the SEP-HEMT exhibits: 1) reduced off-state leakage current and enhanced breakdown voltage, attributed to optimized electric field distribution enabled by the extended p-GaN (EP) regions and 2) improved dynamic characteristics from suppressed parasitic effects in the segmented architecture. The dynamic behavior of the devices is investigated through pulsed I–V measurements, where the SEP-HEMT demonstrates the lowest dynamic degradation among the evaluated structures. Electroluminescence (EL) characterization reveals distinct EL emission from the p-GaN extension regions under on-state bias, verifying potential lift-up in EP regions. Furthermore, EL mapping under semi-on conditions directly visualizes depletion region expansion with increasing drain bias, demonstrating effective peak electric field smoothing. The SEP structure offers an effective solution for optimizing dynamic on-resistance degradation in p-GaN gate HEMTs.