Department of Mechanical Engineering
Kenneth E. Goodson
Touzelbaev, M.N., and Goodson K.E., 1997, "Impact of Nucleation Density on Thermal Resistance Near Diamond-Substrate Boundaries," AIAA Journal of Thermophysics and Heat Transfer, Vol. 11, pp. 506-512.
The measured thermal resistance between deposited layers and substrates at room temperature is not well predicted by existing theory. This may result, in part, from microstructural disorder in the deposited within tens of nanometers of the interface. The present manuscript develops a model for the thermal resistance near diamond-substrate interfaces, where the best deposition processes continue to yield high concentrations of amorphous inclusions and nanocrystalline material. The model relies on phonon transport theory and a novel subdivision of the near-interfacial region, which shows that the resistance is governed by the number of diamond nucleation sites per unit substrate area, i.e., the nucleation density. The predictions are consistent with experimental data for diamond– silicon interfaces, and indicate that the resistance reaches a minimum for a nucleation density near 10^10 cm^-2. This work facilitates the development of microstructures that benefit more strongly from the excellent thermal-conduction properties of diamond.