Investigation of AlGaN Channel HEMTs on β-Ga2O3 Substrate for High-Power Electronics

Carlos Andrés Tavera Romero,C S Boopathi,A Revathy,Osamah Ibrahim Khalaf

doi:10.3390/electronics11020225

Abstract

The wider bandgap AlGaN (Eg > 3.4 eV) channel-based high electron mobility transistors (HEMTs) are more effective for high voltage operation. High critical electric field and high saturation velocity are the major advantages of AlGaN channel HEMTs, which push the power electronics to a greater operating regime. In this article, we present the DC characteristics of 0.8 µm gate length (LG) and 1 µm gate-drain distance (LGD) AlGaN channel-based high electron mobility transistors (HEMTs) on ultra-wide bandgap β-Ga2O3 Substrate. The β-Ga2O3 substrate is cost-effective, available in large wafer size and has low lattice mismatch (0 to 2.4%) with AlGaN alloys compared to conventional SiC and Si substrates. A physics-based numerical simulation was performed to investigate the DC characteristics of the HEMTs. The proposed HEMT exhibits sheet charge density (ns) of 1.05 × 1013 cm−2, a peak on-state drain current (IDS) of 1.35 A/mm, DC transconductance (gm) of 277 mS/mm. The ultra-wide bandgap AlGaN channel HEMT on β-Ga2O3 substrate with conventional rectangular gate structure showed 244 V off-state breakdown voltage (VBR) and field plate gate device showed 350 V. The AlGaN channel HEMTs on β-Ga2O3 substrate showed an excellent performance in ION/IOFF and VBR. The high performance of the proposed HEMTs on β-Ga2O3 substrate is suitable for future portable power converters, automotive, and avionics applications.

Highlights

Group III-nitride-based heterostructure devices showed excellent performance in highpower switching electronics [1,2,3]
There is a wide bandgap and superior thermal stability in AlGaN material adopted as a channel for improving the high-power handling and high-temperature operations of high electron mobility transistors (HEMTs)
The current driving (J = qvns ) capability of the HEMTs relies on the electron velocity (v), sheet charge, and 2DEG density

Summary

Introduction

Group III-nitride-based heterostructure devices showed excellent performance in highpower switching electronics [1,2,3]. The wide bandgap (4.7 eV), high critical electric field (6–8 MV/cm), large-scale, high-quality bulk substrate, low defect density, and nearly lattice match (0 to 2.4% lattice mismatch for AlGaN alloys) with III-Nitride alloys make β-Ga2 O3 a promising material for future high-power applications [12,13,14,15,16,17,18]. The first Al0.1 Ga0.9 N channel-based HEMTs on the β-Ga2 O3 substrate is proposed in this work for simultaneous improvement in both power handling and current driving capability of HEMTs. The proposed gate field plate Al0.31 Ga0.69 N/Al0.1 Ga0.9 N HEMTs on βGa2 O3 substrate is investigated using ATLAS TCAD [20] and the device DC characteristics are presented. The field plate gate low Al composition (Al = 10%) AlGaN channel HEMT on β-Ga2 O3 substrate showed remarkable improvement in breakdown voltage (VBR ), on-state drain current density, and low on-resistance

Device Structure and Simulation Model

Results and Discussions

Conclusions