Computer Simulation Of The Thin Film Initial Growth

The micro movement of deposited cluster and the microstructure evolution of thin film have been studied in dimension of atom-cluster in this paper. There are some important applications to do deeply research on the migration, coacervation and nucleation of atom cluster, to optimize the deposition process, to enhance the characteristics of thin film。The thin film growth process is simulated by Monte Carlo (MC) method. By varying the surface morphology of a substrate,the effect of substrate pre-treatment on nucleation is explored in this paper. A set of sound arithmetic are introduced by choosing proper potential function, Hamiltonian and physical parameters, the diffusion probabilities of active particles of all instability clusters on the surface are taken account of. The model simulates the microstructure evolution of thin film in the initial stages of deposition process successfully. On the results, the particle amount of a certain cluster is proposed. The sum of clusters dropped, the average size of cluster and the average step of atomic diffusion related to temperature and the time of growth are obtained. Analyzing the results by using the Molecular Dynamics method, the concept of critical nucleus and the interactive range are well proved in the results.The results of simulation indicate that the stay time, diffusion step and nucleation density depend on surface morphology, the original energy of sink particles, adsorption energy and substrate temperature. With the temperate increasing, the total of diffusion steps becomes big. The number of atom-clusters increases then decreases. And the size of atom-clusters increases during the same depositing time. In the depositing process, deposited clusters primarily nucleate and grow before the number of atom clusters reached the critical size. Deposited clusters do not fill in the maze until the continuous film shapes.