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

A segmented-extended <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</i>-GaN (SEP) gate structure is proposed and implemented in a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</i>-GaN/ AlGaN/GaN high-electron-mobility transistor (HEMT). Compared to conventional <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</i>-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 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">I</i>–<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> measurements, where the SEP-HEMT demonstrates the lowest dynamic degradation among the evaluated structures. Electroluminescence (EL) characterization reveals distinct EL emission from the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</i>-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 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</i>-GaN gate HEMTs.