Monte Carlo simulations of epitaxial thin film growth

Using kinetic Monte Carlo simulations of well-known simple diffusion-limited 1+1 and 2+1 dimensional growth models and 2+1 dimensional homoepitaxial and binary alloy film growth models with a realistic Arrhenius diffusion, we present extensive simulational results for the detailed shape of the normalized height distributions of a growing surface and growth-induced surface roughening and domain growth.;We use a solid-on-solid model with periodic boundary conditions. Various types of Arrhenius diffusion dynamics and random deposition of particles are used for epitaxial binary alloy (AxB 1--x) films grown on an A-type substrate with nearest-neighbor interactions and the concentration x = 0.5. The homoepitaxial growth model corresponds to the case of x = 1 in binary alloy models.;A detailed shape of the height distributions for the simple models has been determined from an exponential fitting, which yields the exponents eta + and eta-- characterizing the shape of distribution. The magnitude of the skewness determines the deviation from a Gaussian height distribution. If a growth model obeys anomalous scaling, we found that the change in the location of the maximum of distributions measured from the mean height shows the same scaling behavior as the interfacial width does.;As the temperature increases, the dynamic exponent z for the homoepitaxial growth model also increases from z = 3.3 to z = 4 but the saturated skewness decreases, indicating that there is a transition from a nonlinear to a linear term as the dominant process in the diffusion dynamics. For high temperatures, the saturated non-equilibrium width shows a linear temperature dependence which is the same as for the equilibrium width. Furthermore, the saturated non-equilibrium width seems to be minimum approximately at the roughening transition temperature. The values of the roughness and dynamic exponents for two random binary alloy models are the same as those for the homoepitaxial growth model at the same temperature regardless of the difference in the diffusion mechanism. However, when inhomogeneous surface diffusion is introduced in the random binary alloy model, scaling of the interfacial width seems to be valid at late times and for large system size, and a systematic deviation in the scaling is manifest at short times.;In the preferential binary alloy model with height restriction, surface tension is a driving force which governs long-time behavior of the alloy films and leads to a logarithmic growth of the interfacial width. The interfacial width for the preferential binary alloy model without such height restriction shows an exponential growth in time and the behavior is quite different from other models considered here. The antiphase boundaries initially induced by the substrate and the random deposition of a binary mixture are eliminated by the coarsening process, leading to a power-law growth of the domain size at late times as the films grow. It seems that the exponent characterizing domain growth depends on models and growth conditions.