Universal Model for Predicting the Thermal Boundary Conductance of a Multilayered-Metal-Dielectric Interface
HT Aller and JA Malen and AJH McGaughey, PHYSICAL REVIEW APPLIED, 15, 064043-I (2021).
A model is developed to predict how the effective thermal boundary conductance (TBC) of a metal cap-metal contact-dielectric junction varies with the contact thickness. Two-temperature-model molecular- dynamics (MD) simulations are applied to qualitatively recreate the experimental observation that the junction TBC increases and then saturates as the contact thickness increases. The MD simulations reveal a strong correlation between the junction TBC and the fraction of the electron-phonon coupling that occurs in the contact versus that in the cap. This correlation is then combined with insights gained from an analytical solution to the two-temperature model in the cap and contact to propose a model that predicts how the TBC varies with contact thickness. The model, which contains no fitting parameters, is validated against more than 100 experimental measurements from the literature on a variety of capcontact-dielectric junctions. By normalizing the TBC and the contact thickness, all the experimental data collapse onto a single curve, with 92% of it lying within +/- 10% of the model. Through physically motivated approximations, the model reduces to a simple thermal circuit that maintains high predictive ability. The population- weighted phonon density of states extracted from the MD simulations suggests that the TBC contact-thickness dependence is strongly influenced by electron-phonon coupling in the contact. The model provides guidance for streamlining the design of thermally efficient electrical contacts.
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