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Molecular dynamics simulations were used to study Ge island nucleation and growth on amorphous SiO 2 substrates. This process is relevant in selective epitaxial growth of Ge on Si, for which SiO 2 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–SiO 2 –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. [ABSTRACT FROM AUTHOR]

Abstract: The growth of uniform thin films on foreign substrates is impeded by several morphological instabilities. Hill-and-valley structures are formed and enhanced during sputter deposition where surface height perturbations have an opportunity to grow to large amplitudes. We show via kinetic Monte Carlo (kMC) simulations that while surface roughness can be partially controlled by changing growth conditions, such as substrate temperature, the diffusion of particles over step edges plays a very important role in determining both surface roughness and the density of the films. Our kMC simulations provide a way to evaluate the strength of surface instabilities during sputter deposition of thin films. [Copyright &y& Elsevier]