Thermal resistance at interfaces

We report measurements of the solid-solid thermal boundary resistance Rbd, spanning the temperature range from 1 to 300 K. Below 30 K, Rbd is found to be in agreement with the prediction of the acoustic mismatch model. The influence of diffuse scattering at the interface is found to have a very minor influence on Rbd. Above 30 K, Rbd decreases less rapidly with increasing temperature than predicted by the theory. Phonon scattering in thin (∼30 Å) disordered layers near the interface is shown to be a possible explanation. Implications for heat removal from integrated circuits are discussed.