Enhancement of heat dissipation in β-Ga2O3 Schottky diodes through Cu-filled thermal vias: experimental and simulation investigations

Abstract

β-Ga₂O₃ with ultrahigh bandgap has emerged as a promising material for next-generation power semiconductors owing to its superior electrical properties. However, its low-thermal conductivity presents challenges for heat dissipation under high-power conditions. In this study, we propose and investigate an efficient device structure for β-Ga₂O₃ devices featuring Cu-filled thermal through-vias to facilitate direct heat dissipation from the channel to the exterior parts. Through-vias were formed in the β-Ga₂O₃ substrate using ultraviolet laser drilling and subsequently filled with highly thermally conductive Cu using electroplating. The thermal performance of the Cu-filled through-vias was assessed by applying low (1.2 W mm⁻³) and high (5.7 W mm⁻³) power settings to the device and analyzing the surface temperature with a high-resolution thermal imaging camera. Finite element simulations were employed to verify the heat dissipation improvement achieved by the thermal vias. Experimental results demonstrate that at 5.7 W mm⁻³, the temperature increase is suppressed by approximately 21%, and the time to reach peak temperature steady-state decreases by approximately 90% when a thermal through-via is used. The simulation results demonstrate a temperature reduction effect of approximately 33%, which is more effective than the experimental observations. Additional simulations indicated that two or more thermal vias with diameters <100 μm symmetrically positioned near the channel could yield heat dissipation improvements over 40%. These findings suggest that Cu-filled thermal vias effectively enhance heat dissipation in high-power β-Ga₂O₃ devices, thereby overcoming limitations associated with their lower thermal conductivities and enhancing their potential as next-generation power semiconductors.