Thin film deposition: fundamentals and modeling

We review some of the principles of thin film growth. We begin with a description of the growth modes of films and relate the different structures to the thermodynamic driving forces and to kinetics. The influence of misfit strain, surface free energies, and interface energies are discussed in detail. In particular, we treat the instability of a moving crystal-vapor surface 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 from molecular dynamics calculations of atomic level energetics and kinetics. Anisotropies in surface energies and surface mobilities are found to be large, and have a strong influence on film structures. An extension of the model to polycrystalline films is included. Some of the issues involved in metallization of silicon devices are discussed using results from this model. (C) 1998 Published by Elsevier Science B.V. All rights reserved.