Monte Carlo simulation of phase separation during thin-film codeposition

Abstract

The results of Monte Carlo simulation of phase separation during binary film coevaporation are presented for a range of deposition conditions. The model employed assumes that phase separation occurs through surface interdiffusion during deposition, while the bulk of the film remains frozen. Simulations were performed on A-B alloy films having compositions of 10 and 50 vol % solute. For both film compositions, the lateral scale of the domains at the film surface evolves to a steady-state size during deposition. A power-law dependence of the steady-state domain size on the inverse deposition rate is obtained. Simulation microstructures at 50 vol % compare favorably with those obtained in a previous experimental study of phase separation during coevaporation of Al-Ge films of the same composition. Results of simulations performed at 10 vol % are compared with the predictions of a theoretical model based on the above assumptions. The power-law exponent obtained from simulations at 10 vol % is different than that predicted by the theoretical model. The reasons for this difference are discussed.