Improving Breakdown Voltage and Threshold Voltage Stability by Clamping Channel Potential for Short-Channel Power p-GaN HEMTs.

Hongyue Wang,Yijun Shi,Yun Huang,Guoguang Lu,Yajie Xin,Chang Liu

doi:10.3390/mi13020176

Abstract

This paper proposes a novel p-GaN HEMT (P-HEMT) by clamping channel potential to improve breakdown voltage (BV) and threshold voltage (VTH) stability. The clamping channel potential for P-HEMT is achieved by a partially-recessed p-GaN layer (PR p-GaN layer). At high drain bias, the two-dimensional electron gas (2DEG) channel under the PR p-GaN layer is depleted to withstand the drain bias. Therefore, the channel potential at the drain-side of the p-GaN layer is clamped to improve BV and VTH stability. Compared with the conventional p-GaN HEMT (C-HEMT), simulation results show that the BV is improved by 120%, and the VTH stability induced by high drain bias is increased by 490% for the same on-resistance. In addition, the influence of the PR p-GaN layers’ length, thickness, doping density on BV and VTH stability is analyzed. The proposed device can be a good reference to improve breakdown voltage and threshold voltage stability for short-channel power p-GaN HEMTs.

Highlights

GaN-based devices are promising for next-generation high-efficiency, high-frequency, high-temperature, and high-power applications due to their superior material properties [1,2,3,4,5,6,7,8]
The structure parameters of conventional p-GaN HEMT (C-HEMT) are designed according to the dissected cross-sectional scanning electron microscope (SEM) images
For C-HEMT, an ionized acceptor concentration Np-GaN = 3.5 × 1017 cm−3 is induced in the p-GaN layer with the tp-GaN = 50 nm, which contributes to V TH and on-state current calibrations for the C-HEMT

Summary

Introduction

GaN-based devices are promising for next-generation high-efficiency, high-frequency, high-temperature, and high-power applications due to their superior material properties [1,2,3,4,5,6,7,8]. According to the application requirements, it is necessary to improve the electric performance of GaN devices [9]. Low on-resistance Ron and high breakdown voltage (BV) for. In order to realize low on-resistance, a short length scheme is always chosen as channel resistance under the gate is the main part of the total resistance for AlGaN/GaN HEMTs [10]. The short channel GaN HEMTs often suffer from the adverse drain-induced barrier lowering (DIBL) effect [11], namely, degradation of forward-blocking characteristics and negative threshold voltage (V TH ) shift at high drain bias [12,13]. In order to suppress the DIBL effect-induced BV degradation, Pinchbeck et al proposed a GaN HEMT with extended gate length to achieve reduced short channel effect and improved BV [14]. Lu et al proposed a dual gate AlGaN

Methods

Results

Conclusion