Thin film deposition: fundamentals and modeling

We review some of the principles of thin film growth. We begin with a descr iption of the growth modes of films and relate the different structures to the thermodynamic driving forces and to kinetics. The influence of misfit s train, surface free energies, and interface energies are discussed in detai l. In particular, we treat the instability of a moving crystal-vapor surfac e resulting from stress, and the stabilizing influence of step energies in the case where the surface is coincident with a low-index orientation below its surface roughening transition temperature. The introduction of defects by strain, high growth rates, and shadowing instabilities are described. A Monte Carlo model of Al is developed; the model parameters are derived fro m molecular dynamics calculations of atomic level energetics and kinetics. Anisotropies in surface energies and surface mobilities are found to be lar ge, and have a strong influence on film structures. An extension of the mod el to polycrystalline films is included. Some of the issues involved in met allization of silicon devices are discussed using results from this model. (C) 1998 Published by Elsevier Science B.V. All rights reserved.