Investigation of Stacked Gate Dielectrics in AlGaN/GaN MOS-HEMTs for High-Voltage Applications

This paper presents a novel AlGaN/GaN metal-oxide-semiconductor high electron mobility transistor (MOS-HEMT) design featuring stacked Al<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>/HfO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> gate dielectrics. Stacked gate oxides as pivotal in the evolution of efficient and reliable GaN MOSHEMTs for advanced electronic and RF systems. The incorporation of Al<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> as a gate insulator effectively lowers gate leakage current (IG-laek), mitigates RF induced current collapse, and manifests excellent thermal robustness. Furthermore, the stacked high-k Hf02 dielectric provides additional benefits, including further suppression of gate leakage, resulting in improved dielectric strength, increased added power efficiency, and a reduced equivalent oxide thickness. The proposed device design achieves significant performance enhancements, including a peak drain-current (ID-.peak] of 376 mA/mm, a maximum transconductance (GM-max) of 104.12 mS/mm, and a cutoff frequency (fT-max) of 61.94 GHz. The dielectric structure presented in this work exhibits and minimal gate leakage, making it an ideal well-suited for demanding high-voltage and high-power uses.