Influence of Substrate and Gate Insulator on the Thermal Characteristics of β-Ga2O3 Field-Effect Transistors: A Simulation Study

Abstract

β-Ga2O3 suffers from extremely poor thermal conductivity, resulting in a severe self-heating effect. Integrating β-Ga2O3 with high-thermal-conductivity foreign substrates is one of the promising solutions to improve the thermal performance of β-Ga2O3 devices. However, the gate insulator also plays an important role in the device’s thermal characteristics. In this work, we analyze the influence of the thermal conductivity of the substrate and gate insulator and the associated thermal boundary conductance (TBC) on the channel peak temperature (TMAX) investigated by the coupled 3-D thermal simulation. It reveals that AlN and SiC substrate could be sufficient compared to the expensive diamond substrate for substrate integration thermal management scheme. And the reduced TMAX becomes more prominent with the high thermal conductivity gate insulator (e.g., h-BN) than with the conventional Al2O3 gate insulator. Furthermore, the TMAX of the device maintains a very high temperature as the TBC is very low (10 MWm−2K−1), indicating the importance of optimizing TBC. Our results provide useful insights into the thermal management of β-Ga2O3 devices.