AlGaN/GaN Dual-Gate HEMT Using a High Al Mole Fraction and Thin Barrier Layer

Abstract

This article examines the use of a high Al mole fraction (x = 0.34) and a thin barrier layer (t = 11.5 nm) in AlGaN/GaN high electron mobility transistors (HEMTs) with both single-gate and dual-gate configurations. Single-gate HEMTs with the current epitaxial structure demonstrated an improved maximum drain current and transconductance, as well as reduced current collapse, compared to similar devices with the reference structure (x = 0.22 and t = 17.5 nm). Furthermore, a dual-gate HEMT with the current epitaxial structure and a gate length of 80 nm showed an extrapolated unity current gain cut-off frequency of 74 GHz and an extrapolated maximum oscillation frequency of 248 GHz, whereas a similar device using the reference structure exhibited values of 63 and 231 GHz, respectively.