MOLECULAR-DYNAMICS SIMULATION OF LOW-ENERGY CLUSTER DEPOSITION DURINGDIFFUSION-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 p reliminary results for deposition of 100-atom clusters. Thin films gro wn via low energy cluster deposition are found to be more three-dimens ional than films grown via single atom deposition. The increased surfa ce roughness can be attributed to the following factors: (i) most depo sition events add atoms to two or more layers; and (ii) the growth of (111) facets on the surface produces many partially exposed atoms. Nei ther of these features was observed during the deposition of single at oms. Thin films grown by deposition of larger clusters tend to be roug her than those produced by smaller clusters at this low temperature. ( C) 1997 Acta Metallurgica Inc.