Deep Submicron Normally Off AlGaN/GaN MOSFET on Silicon with VTH > 5V and On‐Current > 0.5 A mm−1

Abstract

A submicron gate normally off AlGaN/GaN high‐electron‐mobility transistor (HEMT) with a high on‐current and high threshold voltage (VTH) is demonstrated. The high‐performance device is realized utilizing a gate recess with a length and depth of 200 and 124 nm, respectively. The recess‐etched region has a roughness of 0.7 nm. Various recess‐etch depths and dielectric annealing conditions are used to tune VTH. The optimized device exhibits an on‐current and VTH of 500 mA mm−1 and 5 V, respectively. The measured breakdown characteristics of the devices and their limitations are investigated using 2D‐technology computer‐aided design (TCAD) device simulation. The penetration of the residual electric field in most of the recess region can be the reason for the premature breakdown of deeply scaled recess‐gate e‐mode HEMTs.