Process-dependent thermal transport properties of silicon-dioxide films deposited using low-pressure chemical vapor deposition

The volumetric heat capacity and thermal conductivity of silicon-dioxide films prepared using low-pressure chemical vapor deposition (LPCVD) are measured. The measurements employ the $\text{3ω}$ technique, which is extended to determine the thermal conductivity anisotropy and volumetric heat capacity of thin dielectric films. The thermal conductivity of the silicon-dioxide films exhibits a significant process dependence, which cannot be attributed to highly oriented microvoids or impurities. The volumetric heat capacity, in contrast, is largely independent of processing history provided that appropriate corrections are made to account for porosity and impurity contributions. This study provides evidence that process-dependent structural disorder strongly influences the thermal conductivity of amorphous films.