Al原子在Pb基底上的沉积过程研究

利用分子动力学方法模拟了Al原子在Pb基底上的沉积过程. 对Al原子在Pb基底(001)面上沉积的形态与Pb原子在Al(001)基底上沉积的形态做了比较. 由于界面间势垒的不同, 两个体系界面间的形态有明显的差异. 分析了基底温度、基底晶面指向、沉积原子的入射动能对界面间原子混合的影响. 模拟结果显示: 随着基底温度升高, 基底原子的可移动性大大增加, 与沉积原子发生较大程度的混合; 入射能的改变对界面间原子的混合影响很小; 基底表面取不同的晶格指向时, 基底与沉积原子间的混合行为也有明显的不同. 利用径向分布函数分析了沉积原子的入射能对薄膜中原子排列有序性的影响. 较高入射能对应更有序的薄膜结构; 由径向分布函数的结构可以推测Al原子在Pb(001)基底表面沉积时界面间可能有金属间化合物生成.关键词：Pb/Al体系沉积过程分子动力学入射能

Atomistic study of deposition process of Al thin film on Pb substrate

The deposition processes for Al atoms on Pb (Al/Pb system) surface and Pb atoms on Al surface (Pb/Al system) are studied using molecular dynamic simulations. Under the same deposition conditions, the morphologies of the two systems are very different due to the difference in energy barrier between the interfaces. The substrate temperature, the atom incident energy, and the surface orientation are discussed in terms of their effects on the atom mixing between interfaces. The simulation results show that with the substrate temperature increasing, atomic mobility is enhanced and the degree of atoms mixing between interfaces becomes greater. However, the change of the atom incident energy has little effect on the atoms mixing between interfaces. The atoms mixing is obviously different due to the change of the surface orientation. The analysis on the pair correlation function g(r) indicates that the film formed with higher incident energy has a better quality. The radial distribution function in peak of the intermixing region reveals that a PbAl intermetallic compound may be formed at the interface between Pb and Al.