Thin film growth modes, wetting and cluster nucleation

Abstract

We discuss the wetting of a crystalline substrate by a deposit, and the equilibrium and metastable configurations that can be expected under various conditions. The stability of different configurations of the deposit was investigated by the use of molecular dynamics techniques. The chemical potential of a uniform film is compared with that or a deposit that aggregates into three-dimensional clusters. In the case where the uniform film is metastable, the rate of nucleation of clusters is calculated in terms of the driving force and the surface and interfacial energies of the system. The degree of misfit between the film and substrate material and the resulting strain in the film is found to have a fundamental role in determining the stability of the structures and nucleation rates. Simulations have been performed using two very different interatomic potentials and crystal structures: (1) the truncated Lennard-Jones potential with the face centered cubic structure, and (2) the Stillinger-Weber potential for silicon with the diamond cubic structure.