A KINETIC MONTE-CARLO SIMULATION OF FIBER TEXTURE FORMATION DURING THIN-FILM DEPOSITION

A modified kinetic Monte Carlo computer simulation has been developed and applied to the investigation of fiber (out-of-plane) texture forma tion in polycrystalline thin films grown in the absence of high-energy bombarding particles. Unlike high-energy deposition, in which texture formation appears to result from a combination of preferential resput tering and self-shadowing at the film surface, the simulation results described herein indicate that texture formation in low-energy deposit ion is caused by a bias in surface diffusion and adsorption energies o n different crystallographic faces. A net flux of atoms toward grains with high-binding-energy faces oriented along the film surface coupled with a greater probability that an atom near the interface between tw o grains will become attached to the high-binding-energy face produces a preferential in-plane expansion of these grains at the expense of t heir neighbors. The rate of texture development is shown to increase w ith increases in the binding energy of the preferred faces and the dep osition temperature, and to decrease with increasing deposition rate a nd initial grain size. Voids and vacancies incorporated into the film form as a result of incomplete layer-by-layer growth induced by condit ions of low surface diffusion and high deposition rate. The density of voids and vacancies, as well as the local surface roughness, varies f rom grain to grain within the material due to the differences in surfa ce diffusion on the crystallographic faces exposed to the deposition f lux as each layer of the various grains is formed. (C) 1997 American I nstitute of Physics.