Growth and properties of Cu thin film deposited on Si(0 0 1) substrate: A molecular dynamics simulation study

Molecular dynamics simulations are used to study the growth and properties of Cu thin film deposited on Si(0 0 1) substrate. In particular, growth mode, crystalline structure and orientation, and surface morphology of Cu thin film are investigated in detail. Our simulation results predict that the growth of Cu thin film on Si substrate is three-dimensional island growth mode. In the growth process, interspecies mixing occurs at the interface between Cu film and Si substrate, and the mixing length increases as the increasing of substrate temperature. Based on the common neighbor analysis of atoms, three crystalline structures in the deposited Cu films are indentified. More important, the formed face-centered cubic (fcc) structure of Cu thin film is (0 0 1) oriented with a rotation by 45° along 〈0 0 1〉 axis when the substrate temperature is 300 K, while the fcc structure of Cu thin film becomes to be (1 1 1) oriented when the substrate temperature is 900 K. The crystalline orientation of deposited film could be explained based on the surface free energy of different crystalline planes as well as the geometrical lattice match rule. In addition, surface roughness of Cu thin film decreases as the increasing of substrate temperature due to the enhancement of surface diffusion.