Thermal conductance of epitaxial interfaces

The thermal conductance of interfaces between epitaxial TiN and single crystal oxides is measured at temperatures between 79. 4 and 294 K using time-domain thermoreflectance. The analysis method relies on the ratio of the in-phase and out-of-phase signals of the lock-in amplifier for more accurate data analysis. The validity of this approach is tested by measurements on 6. 5, 11. 8, and 25 nm thick thermally oxidized SiO₂ on Si. The thermal conductances G of TiN/MgO (001), TiN/MgO (111), and TiN/Al₂O₃ (0001) interfaces are essentially identical and in good agreement with the predictions of lattice dynamics models and the diffuse mismatch model with a four-atom fcc unit cell. Near room temperature, G700{0ex{0ex}MWm}^-20ex{0ex}K^-1, 5 times larger than the highest values reported previously for any individual interface.