Atomistic simulations of G-type phonons in silicon devices

Heat conduction in highly compact silicon transistors is impeded due to localization of the electronically generated heat in the device drain. This work studies phonon transport from such heat sources using parallel molecular dynamics. Device Monte Carlo calculations provide an estimate of the size and energy density of the phonon source which is embedded in a one-dimensional crystal. We calculate the scattering times and decay channels for the excited phonons in the absence of thermal phonons. The hotspot is evolved in time and resulting atomic displacements are Fourier analyzed for various phonon modes. Simulations show that decay channels differ depending on the initial energy density of the hotspot. This approach provides a novel method of extracting anharmonic phonon scattering rates for non-equilibrium conditions in a transistor, where first order perturbation theory based calculations may be inaccurate.