Direct molecular dynamics simulation of Ge deposition on amorphous SiO2 at experimentally relevant conditions

Molecular dynamics simulations were used to study Ge island nucleation and growth on amorphous SiO2 substrates. This process is relevant in selective epitaxial growth of Ge on Si, for which SiO2 is often used as a template mask The islanding process was studied over a wide range of temperatures and fluxes, using a recently proposed empirical potential model for the Si-SiO2-Ge system. The simulations provide an excellent quantitative picture of the Ge islanding and compare well with detailed experimental measurements. These quantitative comparisons were enabled by an analytical rate model as a bridge between simulations and experiments despite the fact that deposition fluxes accessible in simulations and experiments are necessarily different by many orders of magnitude. In particular, the simulations led to accurate predictions of the critical island size and the scaling of island density as a function of temperature. The overall approach used here should be useful not just for future studies in this particular system, but also for molecular simulations of deposition in other materials. (C) 2015 Elsevier B.V. All rights reserved.