Design and analysis of normally-off GaN-HEMT using β-Ga2O3 buffer for low-loss power converter applications

Abstract

An enhancement mode HETM with β-Ga2O3 buffer is proposed, and its electrical characteristics are analyzed using the physics-based numerical simulator ATLAS TCAD. HEMT with p-GaN/AlGaN/GaN/β-Ga2O3 utilized for normally-off mode operation of HEMT. The proposed β-Ga2O3 buffer based HEMT in this work reveals low on-resistance (Ron), high drain current density (IDS,max), high transconductance (gm,max), excellent breakdown voltage (VBR) and low gate switching delay. The ultra-wide bandgap β-Ga2O3 (EG ∼ 4.7 eV) buffer on silicon carbide (SiC) substrate HEMT mitigates the interface-related traps due to nearly lattice match with GaN and suppressing buffer leakage current by serving as a natural back-barrier. This β-Ga2O3 back-barrier structure increases the 2DEG (two-dimensional electron gas) and mitigates buffer leakage currents. Numerical simulation shows IDS,max of 0.95 A/mm, Ron of 4.26 Ω mm, and VBR of 835 V. for LG = 0.8 μm HEMT. The excellent device characteristics indicate the merits of β-Ga2O3 buffer-based normally-off HEMT for medium voltage range (<800 V) low resistive loss power converters applications.