AlScN/GaN HEMTs with 4 A/mm on-current and maximum oscillation frequency >130 GHz

Abstract

Abstract Aluminum Scandium Nitride (AlScN) is an attractive material for use as a lattice-matched epitaxial barrier layer in GaN high-electron mobility transistors (HEMTs). Here we report the device fabrication, direct current (DC) and radio frequency (RF) characteristics of epitaxial AlScN/AlN/GaN HEMTs on SiC substrates with regrown ohmic contacts. These devices show record high on-current of over 4 A/mm, high cutoff frequency ( f T ) of 92.4 GHz and maximum oscillation frequency ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>f</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">MAX</mml:mi> </mml:mrow> </mml:msub> </mml:math> ) of 134.3 GHz.