Enhancing interfacial thermal transport in GaN-diamond heterointerfaces through thermally induced mixing layers

Abstract Understanding interfacial phonon transport is critical for optimizing thermal management in high-power GaN-based microelectronic devices. Here, we employ molecular dynamics simulations to investigate the impact of two different amorphous GaN/diamond (a-GaN/a-diamond) interfacial structures on thermal transport across the GaN-diamond interface. The results reveal that the presence of a-GaN/a-diamond significantly hinders interfacial thermal transport due to phonon mismatch. However, introducing an amorphous mixing layer (formed by annealing a-GaN/a-diamond) reduces the phonon mismatch and enhances phonon mode participation, thereby increasing interfacial thermal conductance (ITC) of the GaN-diamond interface. Specifically, the ITC of the GaN-diamond interface with the mixing layer is 67% higher than that with a-GaN/a-diamond (total thickness of 5 nm). These findings demonstrate that the formation of thermally induced mixing layer is a promising strategy for improving interfacial thermal transport in GaN-diamond heterointerfaces. This work provides important insights for engineering advanced interface designs to optimize the thermal management in GaN-based power devices.