低能Cu原子簇沉积薄膜的分子动力学模拟

用分子动力学计算机模拟研究了能量为5—20eV/atorn,结构为正二十面体的(Cu)₁₃原子簇在Cu（001）表面的沉积过程.采用紧束缚势同Moliers势的结合描述Cu原子间相互作用通过原子簇-衬底相互作用的“快照”研究沉积的动态过程．结果表明,当入射能量较低时,轰击弛豫后,入射原子簇在衬底表面发生重构,生成很好的外延层,靶没有任何损伤．随着轰击能量的增加,原子簇原子穿入靶的深度增加.当入射能量达到20eV/atom时,原子簇完全穿入靶并开始造成辐照损伤,表面出现空位,靶内产生间

MOLECULAR-DYNAMICS SIMULATIONS OF SLOW COPPER CLUSTERS DEPOSITION

The depositing process of (Cu)₁₃ cluster, on Cu(001) surface with icosahedral structure and en-ergy ranging from 5 to 20 eV per atom, is investigated by molecular-dynamics simulations. A many-body hybrid potential, which is a combination of the tight-binding with Moliere potential, is used. The dynamic behavior of deposition is studied by taking the "snapshots" of cluster-substrate interac-tion. It is found that the cluster atoms rearrange and form epitaxial layers on the surface without cre-ating point defects after full relaxation at low energy. A clear trend of deeper penetration of the clus-ter atoms into the substrate with increasing energy is observed. A cluster with energy 20 eV per atom completely embeds itself inside the substrate while creating radiation damage. Energy analyses show that the cluster atoms activate the substrate atoms in impact regjon through collective collisions in a very short time (some tenth picoseconds), and provide energies for the migration and reconstruction of atoms.