Updated Model for Thermal Conductivity Calculation of Thin Films of Silicon and Germanium

A model for calculation of thermal conductivity of thin films of silicon and germanium is presented on the basis of solving the Boltzmann equation in the time relaxation approximation. The unique feature of this model is the application of recent achievements in determination of the time of phonon–phonon interactions obtained from “first principles” and also the use of real dispersion curves and the propagation velocities of phonons with different polarization. The proposed approach contains no averaging and fitting parameters, which already for more than half a century and until now have been common in calculations of thermal conductivity of macroscopic bodies and nanostructures. A detailed qualitative and quantitative comparison of results of calculations by the “classical” and “updated” models is carried out. Problems in the methods for calculating thermal conductivity for simulation of new structures in advanced semiconductor devices and ways of their further development are set forth.