Multi-lattice Monte Carlo model of thin films

Abstract

In previous publications, an atomistic simulator based on a single-lattice or a dual-lattice Monte Carlo method has been proposed and applied to the studies of microstructure evolution in thin films. In this paper, a multi-lattice Monte Carlo model, an extension to our atomistic simulator of deposition in three dimensions (ADEPT), is presented and applied to the studies of texture competition in thin films. Multiple lattices are mapped onto a single reference lattice, with resulting computational demands (memory and speed) being comparable to those in the single-lattice Monte Carlo model. It is therefore possible to simulate growth competition among crystallites of different orientations, and to study texture formation and explore optimal deposition conditions. As an application, the predominant texture is investigated as a function of collimation and deposition rate. Grains with low energy surfaces parallel to the substrate are found to dominate under the condition of low deposition rate and collimated beam. On the other hand, grains with high surface energy are found to dominate for high deposition rate and uncollimated sputtered beam, and their dominance disappears at extremely high deposition rates.