THE GROWTH DYNAMICS OF ENERGETIC CLUSTER-IMPACT FILMS

Dense and smooth thin films can be produced by the deposition of energ etic clusters onto a solid surface. Roughnes, induced by random deposi tion of the clusters, is strongly suppressed by a downhill smoothing p rocess. Molecular dynamic simulations of the impact of copper clusters onto tilted copper surfaces demonstrate that a downhill particle curr ent proportional to the local slope of the surface is initiated. In th e long wavelength limit the evolution of the surface profile is govern ed by the Edwards-Wilkinson equation. One parameter in this equation i s related to the strength of the downhill movement due to the cluster impact and can be determined from the simulations. From the solution o f the spatially Fourier transformed growth equation the power spectrum is calculated, which is in agreement with atomic force microscopy mea surements for copper films. Copyright (C) 1998 Elsevier Science B.V.