>2.7 kV Al0.65Ga0.35N Channel HEMT on Bulk AlN Substrate With >400 MW/cm² Baliga Figure of Merit

Al-rich AlGaN has emerged as a promising material for high-voltage power electronics due to its exceptional critical electric field (>10 MV/cm). In this work, we demonstrate passivated and field-plated high voltage Al<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.65</sub>Ga<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.35</sub>N channel transistors. For >2.7 kV breakdown voltage, a high Baliga figure of merit (BFOM) of close to 400 MW/cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> using gate pad connected and source pad connected field plates were obtained for Al<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.65</sub>Ga<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.35</sub>N channel HEMTs. Additionally, we also report a non-passivated Al<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.65</sub>Ga<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.35</sub>N channel HEMTs with >3 kV breakdown voltage and a high BFOM of 569 MW/cm². Furthermore, a low contact resistance of ~2.6 Ω·mm for >60% AlGaN channel FETs on bulk AlN substrates was also obtained. These results provide advances which will help establish AlGaN channel transistors as a compelling candidate for next-generation high-voltage power electronics.