Thermal boundary conductance in heterogeneous integration between β-Ga2O3 and semiconductors

As an emerging wide-bandgap semiconductor material, β-Ga2O3 has extensive application prospect in high power operating environments due to its excellent electrical properties, but low thermal conductivity and anisotropy bring challenges in device heat dissipation. Heterogeneous integration of β-Ga2O3 with high thermal conductivity substrates might improve thermal dissipation efficiency and device operational stability. However, heterogeneous integration introduces thermal boundary resistance (TBR) between the β-Ga2O3 and the substrate, and it is necessary to investigate proper heterogeneous integration processes to reduce the TBR. In this work, we compare the thermal boundary conductance (TBC) between Ga2O3 and different semiconductors with the Acoustic Mismatch Model (AMM) and Diffusion Mismatch Model (DMM). Molecular dynamics (MD) simulations show that the [010] crystallographic direction of β-Ga2O3 exhibited the highest thermal conductivity and higher TBC with most semiconductors except BN and Diamond. To enhance the thermal transport between β-Ga2O3 and the most widely used SiC substrate, SiO2 thin film is introduced as an interlayer, and the TBC is enhanced by 3.7 folds. The SiO2 interlayer can bridge the vibration between β-Ga2O3 and SiC by improving the overlap energy and phonon participation ratio. These research findings provide guides for the selection of substrates and interlayers in heterogeneous integration for β-Ga2O3 device thermal management.