Heat transport evaluation of amorphous Si, SiGe, and Ge thin films using 3ω method and minimum heat conduction model

Abstract

Heat transport properties of amorphous Si, SiGe and Ge thin films were investigated by comparing measured and theoretical thermal conductivities. The thermal conductivity was measured by the 3ω method. The theoretical thermal conductivity was calculated using the minimum heat transfer model based on the Einstein model, which is close to the heat transport in amorphous materials. The theoretical thermal conductivity was determined from the minimum heat transfer model with the phonon group velocity measured from the Young's modulus using the nanoindentation. The measured thermal conductivities of three types of the thin films approximately corresponds to those of theoretical thermal conductivities because they obtained amorphous structures. However, the measured and theoretical thermal conductivities of the three thin films followed the order of Si > Ge> SiGe and Si > SiGe > Ge, respectively. This difference occurred because the measured thermal conductivities included the effect of the interaction of different types of atoms, while the theoretical values did not account for this effect.