Thermal conductivity of amorphous and crystalline thin films by molecular dynamics simulation

Thermal conductivity (TC) of thin films will be influenced by boundary if the thickness is close to the mean free path (MFP). In this paper, we calculate the TC of crystalline and amorphous SiO2 thin films, which are commonly used materials in micro devices and Integrated Circuits, by nonequilibrium molecular dynamics (NEMD) simulations. The calculation temperatures are from 100 to 700 K and the thicknesses are from 2 to 8 nm. For crystalline thin films, thickness is less than MFP, for amorphous thin films, the thickness is larger than MFP. The TC of crystalline thin films reach their peak values at different temperatures for different thicknesses, the smaller thickness, the larger peak value obtained. But for amorphous thin films, the results show that the temperature dependence of thin films is similar to bulk materials. The obtained temperature dependence of the thin films is consistent with some previous measurements and the theory predictions.