Gate-Recessed InAlN/GaN HEMTs on SiC Substrate With $ \hbox{Al}_{2}\hbox{O}_{3}$ Passivation

Abstract

We studied submicrometer (L <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">G</sub> = 0.15-0.25 ¿m) gate-recessed InAlN/AlN/GaN high-electron mobility transistors (HEMTs) on SiC substrates with 25-nm Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> passivation. The combination of a low-damage gate-recess technology and the low sheet resistance of the InAlN/AlN/GaN structure resulted in HEMTs with a maximum dc output current density of I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DS,max</sub> = 1.5 A/mm and a record peak extrinsic transconductance of g <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m,ext</sub> = 675 mS/mm. The thin Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> passivation improved the sheet resistance and the transconductance of these devices by 15% and 25%, respectively, at the same time that it effectively suppressed current collapse.