Non-uniform Computer Simulation Of Thin Film Growth On The Substrate

In the thesis, we investigate submonolayer and multilayers film growth process, especially study the influence of surface heterogeneities on adatoms diffusion and aggregation.Simulation of film growth on heterogeneous surface is a new field. Firstly, the heterogeneous substrate model is introduced after analyzing MBE. In reality, the actual surface where film grow is usually not perfect, and defects and impurities are common. They can be regarded as heterogeneities of substrate. These surfaces are always complicated. It is difficult to investigate the influence of heterogeneities of these actual surfaces on adatoms diffusion and aggregation. This so-called bivariate chessboard-like substrate model is introduced, because the pattern can be generated easily on the computer. This model is suitable to describe the general situation where the correlation between the adsorptive energies of two sites decreases with the distance between them. It adsorbs advantages of PHS and IS models.In this model, sites are not random and they are correlated. The size of patches consisted of the same kind sites are to describe the correlation between sites.Secondly, the diffusion-limited aggregation on heterogenous square and triangle substrates is simulated. The results indicate that the aggregation is different from on homogeneous substrate. We analyze the difference between them using FIPS software (Sandbox method) to calculate the fractal dimension. After studying DLA on heterogenous surface, we concentrate on film growth. Since there are more than one aggregate centers, the phenomena is different from DLA. In the thesis, the influence of substrate energetic topology on the main feature of island is investigated too. It is found that the growth process and island morphology are governed by surface energetic topology. Then we get the relation function between the island number and surface energetic heterogeneities using computer simulation. It is found that the number of island is static when the adsorption difference between the different patch change in special condition.After studying submonolayer film growth, we continue to study multilayers film growth on heterogenous substrate. The multilayers film growth process is so complicated that we are forced to simplify the model. The submonolayers film growth is simulated by three dimension model,and the results agree with the two dimension...