The low energy ion assisted control of interfacial structure: Ion incident energy effects

The properties of multilayered materials are often dependent upon their interfacial structure. For low temperature deposition processes where the structure is kinetically controlled, the interfacial roughness and the extent of interlayer mixing are primarily controlled by the adatom energy used in the deposition. Inert gas ion assistance during the growth process also enables manipulation of the interfacial roughness and intermixing. To explore inert gas ion assistance, a molecular dynamics approach has been used to investigate the role of ion energy and ion species upon the flattening of various surfaces formed during the growth of the Ni/Cu/Ni multilayers. The results indicated that ion energies in the 1–4 eV range could flatten the ‘‘rough’’ copper islands on either copper or nickel crystals. To flatten the rough nickel islands on copper or nickel crystals, higher ion energies in the 9–15 eV range would have to be used. Significant mixing between nickel island atoms and the underlying copper crystal atoms started to occur as the ion energy was increased to around 6–9 eV. However, little mixing was observed between the copper island atoms and the underlying nickel crystal atoms in the same ion energy range. At a given ion energy, the heavier ~xenon! ions were found to produce more surface flattening and mixing than the lighter ~argon! ions. © 2000 American Institute of Physics. @S0021-8979~00!03512-X#