超薄膜生长的Monte Carlo模拟研究

Monte Carlo simulation and study of thin film growth process

利用Monte Carlo(MC)方法模拟研究了薄膜生长的初始阶段岛的形貌和岛的尺寸与基底温度和入射粒子剩余能量之间的关系.模型中考虑了粒子的沉积、吸附粒子的扩散和蒸发等过程.结果表明当基底温度从200K变化到260K时,岛的形貌经历了一个从分散生长逐渐过渡到分形生长的过程,并且在较低温度(200K)下,随入射粒子剩余能量的增加,岛的形貌也经历了同样的变化过程.进一步研究证明,随着基底温度的升高或入射粒子剩余能量的增加,沉积粒子的扩散能力显著增强,从而使岛的形貌发生了改变.

The effect of the substrate temperature and the rest energy of incident particles on the island morphology and size at the early stage of thin film growth are studied by Monte-Carlo simulation. In our model, three processes are considered： particle deposition, adatom diffusion and adatom reevaporation. The results show that, with temperature increasing from 200 K to 260 K, the island growth transits from sporadic to fractal shape, as the temperature is relatively low （200 K）, with increasing rest energy of incident particles, the same evolution of island morphology is also observed. Further study shows that, with increasing temperature or increasing rest energy of incident particles, diffusivity of deposit particles is prominently improved, then island morphology is changed.