Comparisons of parameters involved in mass transport and desorption at the surface of noble metals and sapphire

In recent works, the morphological evolutions of thin metal films have been followed by Auger electron spectroscopy, scanning electron microscopy and atomic force microscopy. From experiments carried out under different microstructural and annealing conditions, mass transfer surface self-diffusion coefficients of metals, mass transfer surface diffusion coefficients of metals on substrates and evaporation rates of adatoms in equilibrium with metal films have been obtained. This paper presents selected results concerning copper, silver, gold and palladium deposited on sapphire, at thicknesses ranging from 0.3 to 20 nm. The activation energies of the different processes are discussed in light of other properties of the metals and metal–alumina systems. In spite of their qualitative nature, the correlations arising from this analysis could provide useful informations on surface mass transport phenomena.