Study of phononic thermal transport across nanostructured interfaces using phonon Monte Carlo method

Abstract

Reducing the phonon-dominated thermal interfacial resistance (TIR) is an effective way to reduce the junction temperature of electronic devices. Several researches have demonstrated that fabricating nanostructures at interface, i.e., constructing nanostructured interface, could significantly enhance the interfacial thermal transport. Here, we conducted a parametrical study on the phononic thermal transport across nanostructured interfaces using phonon Monte Carlo (MC) technique, and analyzed the dependence of effective thermal resistance ratio between the nanostructured and planar interfaces on the various parameters and the heat flux distributions. Our simulations and analyses indicate that the interfacial thermal transport improvement should be attributed to two mechanisms: the change of heat conduction pathways resulted from the interfacial nanostructures and the phonon transmission enhancement induced by the multiple reflection at the interface. The former is predominant when the diffusive transport dominates, while the latter becomes dominant with the enhancement of ballistic transport effect. Additionally, the diffuse scattering of phonons at the interface, which is enhanced with the increasing interface roughness, has a strong negative effect on the improvement of interfacial thermal transport. Due to the combination of those three mechanisms above, the effective thermal resistance ratio decreases to a minimum value and then increases with the increasing contacting area. The present work provides a more in-depth understanding on the interfacial thermal transport in nanostructured interfaces, and can be helpful for the thermal management of electronic devices.