Kinetic Monte Carlo Simulation Of Thin Film Epitaxial Growth

The thin film growth mechanism is the primary content in thin film research. With the rapidly development of modern information science and technology, functional devices are developing toward the miniaturization and integration. How to manufacture high-quality thin film is very important. The initial growth mode of the thin film influence the quality of the whole film, so it will improve the technical skill to research the film growth law from atomic scale. Recently, people study the thin film mainly by the experiments and computer simulation, in this paper, we used computer simulation.Through our understanding of submono layer nucleation law and micro-motion process of particles, the film morphology of thin film epitaxial growth of two different atoms were simulated by use of Kinetic Monte Carlo method in this paper. A two-dimensional and stressless model was used and the periodic boundary condition was taken into account. Suppose one-dimensional flat lattice as to the substrate, we only considered two kinds of processes of the deposition and the diffusion of adatoms on the growth surface. Then the surfactant-mediated thin film epitaxial growth, which did not consider special materials and configuration of atoms, was simulated and analyzed.Firstly, the morphologies of thin film were simulated when considering surfactants; regarding to the influence of interatomic interaction energy on surfactant atoms, the simulation results indicated that the surfactant atoms can display floating behavior only when interatomic interaction energy satisfied the conditions EAA> EBB and(EAA+EBB-2EAB)>0.Secondly, the influence of growth temperature on up-floating behavior of surfactant atoms was simulated under the condition of above-mentioned prerequisite worked, and the morphology of thin film under different growth temperature after the change of interatomic bond energies, the simulation results showed that the up-floating ability of atoms was strengthened with temperature rising and almost all the surfactant atoms can float to the top positions through exchange interaction when the temperature was high enough, moreover, the surfactant atoms can show floating behavior only when the temperature was over the certain critical point; the morphology of thin film was different when interatomic bond energies changed, so it was not unique when choosing the surfactants.Finally, the different morphologies of nanoculsters growth were simulated when we deposited atoms under the conditions of without and with a single layer A atoms substrate. The influences of the growth temperature, deposition rate and lattice length of substrate on nanoculsters growth were also simulated. The results are given as follows:When deposited atoms without a single layer A atoms substrate the large size of nanoculsters can be formed in the inner of thin film; when deposited at the substrate of a single layer of A atoms, a lot of discrete small nanoculsters were grown and B atoms exhibited the floating behavior; In our simulation, the size of nanoculsters became larger as the growth temperature increasing, the change of nanoculsters size were not obvious as deposition rate increasing, the different lattice length of substrate did not affect the morphology of nanoculsters.