Monte Carlo study of phonon transport in solid thin films including dispersion and polarization

The Boltzmann Transport Equation (BTE) for phonons best describes the heat flow in solid nonmetallic thin films. The BTE, in its most general form, ho wever, is difficult to solve analytically or even numerically using determi nistic approaches. Post research has enabled its solution by neglecting imp ortant effects such as dispersion and interactions between the longitudinal and transverse Polarizations of phonon propagation. In this article, a com prehensive Monte Carlo solution technique of the BTE is presented. The meth od accounts for dual polarizations of phonon propagation, and non-linear di spersion relationships. Scattering by various mechanisms is treated individ ually. Transition between the two polarization branches, and creation and d estruction of phonons duc to scattering is taken into account. The code has been verified and evaluated by close examination of its ability or failure to capture various regimes of phonon transport ranging from diffusive to t he ballistic limit. Validation results show close agreement with experiment al data for silicon thin films with and without doping. Simulation results show that above 100 K, transverse acoustic phonons are the primary, carrier s of energy in silicon.