Molecular dynamics simulation of low energy cluster deposition during diffusion-limited thin film growth

Molecular dynamics simulations permit multiple-layer thin film growth to be studied in detail, using reliable interatomic potentials for fee metals from corrected effective medium theory. Results are presented for the homoepitaxial deposition of 20 ML on Pd(001) and Cu(001) near 0 K via low energy deposition of 5- and IO-atom clusters, along with preliminary results for deposition of 100-atom clusters. Thin films grown via low energy cluster deposition are found to be more three-dimensional than films grown via single atom deposition. The increased surface roughness can be attributed to the following factors: (i) most deposition events add atoms to two or more layers; and (ii) the growth of (111) facets on the surface produces many partially exposed atoms. Neither of these features was observed during the deposition of single atoms. Thin films grown by deposition of larger clusters tend to be rougher than those produced by smaller clusters at this low temperature. (C) 1997 Acta Metallurgica Inc.