Characterization of the growth dynamics of Al/Si(100) using kinetic Monte Carlo approach

Abstract

We performed kinetic Monte Carlo simulations of a realistic atomistic lattice-gas model to investigate the dynamics of Al adsorption on Si(100):2x1 at submonolayer regime with varying deposition temperatures (T) and coverage (θ). An adatom-tracking algorithm were implemented to determine the frequency of visit on a certain lattice site (F_V), frequency gradient of visit relative to the nearest-neighbors (F_G) and the mean frequency of visit for the whole lattice (F_M). Results show that the F_V increases with θ and T; an indication of increased adatom mobility. Moreover, increases in the adatom mobility which consequently resulted in longer diffusion length at 500 K resulted to a uniform distribution of F_V among sites. In addition, the probability of size-dependent attachment P_SDA (s) vs. island size s was obtained under various coverages (0.05 ML - 0.30 ML). Results show a monotonically decreasing distribution of P_SDA (s) vs. s curve at low temperature (100 K) and high coverage (0.15 ML - 0.30 ML). In contrast, a monomodal P_SDA (s) vs. s curve was observed at low coverage (0.05 ML - 0.10 ML) and high temperature (400 K - 500 K); an observation attributed to high diffusion events at high temperatures. The result of this study is consistent with the Arrhenius behavior observed in the same system, wherein island size increases with temperature until reaching a transition temperature of 400 K, where the island size starts to decrease.