Kinetic Monte Carlo Simulation Of Anisotropic Growth Of Ultra-thin Films

The microscopic condensed behavior of adatoms in the initial stage of thin film growth plays an important role in the properties of thin film and of devices. In the processes of thin film growth, the property of anisotropy is common, such as anisotropic structure of substrates, anisotropic diffusion of deposited atoms and anisotropic reaction between adatoms and islands. All the anisotropic properties will influence dramatically to the processes of thin films, morphologies of thin films and characters of thin films.In chapter 2, based on the anisotropy of atomic structure of substrates, the kinetic Mont Carlo simulation model is presented to investigate the formation of thin films on heterogeneous surface (including square and triangular surfaces). We focus on the influence of topography of substrate and surface energetic heterogeneities on the morphologies of thin film growth and main features of fractal aggregates. On the other hand, the processes of adatom diffusion and thin film growth as well as the formation of the growth mode "step flow" on the substrates with steps are also simulated by means of Mont Carlo method. The simulation results can explain the corresponding experiemts well.In chapter 3, based on the anisotropy of atomic diffusion, a kinetic Monte Carlo simulation model is presented, by using realistic thin film system and physical parameters so as to investigate the atomic process of anisotropic diffusion and the morphologies of anisotropic growth of thin films on hexagonal substrates. By taking into account the influence of the concentration of ions in the solution, the probability of reaction and the probability of directional excursion, the fractal growth of ultra-thin films via electrochemical deposition and the influence of the physical and chemical parameters on the formation of ultra-thin films is simulated. The atomic processes of diffusion and dendritic cluster formation under a invariable magnetic field are also simulated so as to study the influence of the magnetic field on the anisotropic growth of thin films. The simulation results are agreement well with the experimental observations.In chapter 4, based on the anisotropy of atomic reaction between adatoms and islands during thin film growth, the microscopic processes of atomic diffusion, reaction and thin film formation on anisotropic metal surfaces and reconstructed semiconductor surfaces are simulated, the morphologies agree well with the experiments and quantity results of thin film growth are obtained. By taking into account the processes of thin film growth, such as deposition, diffusion, nucleation, growth, evaporation, edge diffusion and coalescence, much of important details of thin film growth at high substrate temperatures such as the changing of island density and growth rate of thin films with temperature and coverage are given after accounting them during the growth processes, which are difficult to get directly in realistic experiments.