High Breakdown Electric Field MIS-Free Fully Recessed-Gate Normally Off AlGaN/GaN HEMT With N2O Plasma Treatment

In this article, the AlGaN barrier fully removed recessed-gate normally off AlGaN/GaN high electron mobility transistors (HEMTs) with N2O plasma treatment are fabricated. The low speed and low damage etching is used in recessed-gate etching, the etching depth is about 26 nm with 0.4 nm remaining, and then, the remaining barrier layer is oxidized by N2O plasma treatment. In the terms of devices' characteristics, the threshold voltage of the recessed-gate HEMT is +1.5 V, and the channel current of recessed-gate HEMTs at V-GS- V-TH = 1.5$ V is about 110 mA/mm. Moreover, 14 mV/V of drain-induced barrier lowering (DIBL) and 70 mV/decade of subthreshold slope (SS) are achieved. More importantly, the fully recessed-gate HEMT shows the average breakdown electric field at V-G = 0 V of about 0.64 MV/cm, which is a very high value in the fully normally off recessed-gate HEMTs without metal insulator semiconductor (MIS) structure, which will be beneficial to the application of this device in the low power supply topology circuit.

Automated summary

This article describes the fabrication of fully removed AlGaN barrier recessed-gate normally off AlGaN/GaN HEMTs with N2O plasma treatment, achieving devices with excellent characteristics and demonstrating a high breakdown electric field value.