High-Current E-Mode InGaN/GaN p-FET on p-GaN Gate HEMT Platform

Abstract

The low current density in E-mode GaN p-FET presents a severe challenge for its application in complementary logic (CL) circuits. In this work, a high-current E-mode InGaN/GaN p-FET is demonstrated on a p-GaN gate HEMT platform with p-InGaN/p-GaN/AlGaN/GaN heterostructure. The proposed heterostructure introduces a net polarization charge at the InGaN/GaN interface, leading to an enhanced 2DHG. With a negative gate bias, a buried 2DHG channel is formed prior to the surface MIS channel. As a result, the recess-gate InGaN/GaN p-FET with LG = 2μm achieves a large maximum current (Imax) exceeding -20 mA/mm. The InGaN/GaN p-FET obtains a low RON of 0.64 kΩ ·mm and a high ION/IOFF ratio exceeding 107. The device presents E-mode operation with a threshold voltage (VTH) of -1.8 V and a low subthreshold swing (SS) of 144 mV/dec. Furthermore, an E-mode n-channel GaN HEMT is fabricated on the same platform, validating the potential of the proposed InGaN/GaN p-FET for GaN CL circuits.