A phenomenological study of the initial stages of film growth

The kinetics of island nucleation, coalescence and growth during deposition of Au atoms on amorphous carbon are studied experimentally and the obtained results are analysed using rate equations. Rutherford backscattering spectroscopy (RBS), transmission electron microscopy (TEM), grazing-incidence small angle scattering (GISAXS) and atomic force microscopy (AFM) techniques are used to measure the quantity of deposited Au, density, size and average height of the islands as a function of time. Parameters used in rate equations are deduced from a quantitative comparison between calculated and experimental evolution of the above dependencies. Suggested rate equations take into account the adsorption rate on a bare substrate as well as on existing islands, the mobility of adatoms, possible redistribution of atoms between islands and bare substrate and coalescence of islands. The rate equations are used to study the kinetics of the coverage of a carbon substrate by gold atoms and the kinetics of the island density. It is shown that experimental and calculated dependencies are in agreement if the mobility of islands is included. (C) 2000 Elsevier Science S.A. All rights reserved.