利用Monte Carlo算法对薄膜生长过程的计算机模拟

用Monte Carlo方法以Cu为例对薄膜生长过程进行计算机模拟．不仅对原子的吸附、迁移及脱附3种过程采用更为合理的模型,还考虑这些过程发生时对近邻原子的连带效应．在合理选择原子间相互作用势计算方法的基础上．改进了原子迁移激活能的计算方法．计算了表征薄膜生长表面形貌的表面粗糙度和表征薄膜内部晶格完整性的相对密度．结果表明,在一定的原子入射率下,表面粗糙度和相对密度的变化存在一个临界温度．随着衬底温度的升高．表面粗糙度减小,膜的相对密度增大．当达到临界温度时,粗糙度随衬底温度的升高开始增大,而相对密度趋于饱和．临界温度随原子入射率的增大而增大,不同温度下原子入射率对粗糙度的影响不同,在较低温度时粗糙度随入射率的增加而增加,在较高温度时粗糙度随入射率增大而减小．同时发现．随入射率的增大或薄膜厚度的增加,相对密度均逐渐减小。

Application of computer: Monte Carlo simulation of thin film growth

A three-dimensional kinetic Monte Carlo (KMC) technique has been developed for simulating growth of thin Cu films. It is based on a model that involves incident atoms attachment,surface diffusion and related effects of the atoms on the growing surface,and atoms detachment from the growing surface. A great improvement was made on calculation of the activation barriers for the surface atoms diffusion. The results showed that there exists a critical temperature at a certain deposition rate,the surface roughness decreases and the relative density increases with the increasing substrate temperature,the surface roughness is minimum and the relative density of film saturates when the substrate temperature approach the critical temperature,and then the surface roughness increases with the increasing substrate temperature. The critical temperature is a function of the deposition rate and it increases with the increasing deposition rate. The influence of the deposition rate to surface roughness is different at various substrate temperatures. With the increasing deposition rate,the surface roughness increases at a lower substrate temperature while it decreases at a higher temperature. The result also shows that the relative density decreases with either the increasing deposition or the increasing average thickness of the film.