Crossplane Phonon Transport and Thermal Boundary Resistance Across Thin Films Pair

Abstract

Crossplane transport of phonons in the silicon and diamond thin films pair is considered, and the thermal boundary resistance is formulated using the cutoff mismatch model at the films pair interface. The transient and frequency-dependent equation for phonon radiative transport is incorporated to simulate the phonon intensity distribution at the interface. Temperature disturbance is introduced at one edge of the silicon film to initiate crossplane phonon transport across the films pair. The thermal boundary resistance predicted from the cutoff mismatch model is compared with that obtained from the diffusive mismatch model. It is found that the cutoff mismatch model predicts higher values of the thermal boundary resistance than that of the diffusive mismatch model. In this case, phonons, which have frequencies mismatching across the interface contribute to the thermal boundary, increase. The thermal boundary resistance predicted from the cutoff mismatch model agrees well with those reported in previous studies. The effect of the silicon film size (width) has a significant effect on the thermal boundary resistance; in which case, reducing the silicon film width lowers the thermal boundary resistance at the interface.