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 obtaine d results are analysed using rate equations. Rutherford backscattering spec troscopy (RBS), transmission electron microscopy (TEM), grazing-incidence s mall angle scattering (GISAXS) and atomic force microscopy (AFM) techniques are used to measure the quantity of deposited Au, density, size and averag e height of the islands as a function of time. Parameters used in rate equa tions are deduced from a quantitative comparison between calculated and exp erimental evolution of the above dependencies. Suggested rate equations tak e into account the adsorption rate on a bare substrate as well as on existi ng islands, the mobility of adatoms, possible redistribution of atoms betwe en islands and bare substrate and coalescence of islands. The rate equation s are used to study the kinetics of the coverage of a carbon substrate by g old atoms and the kinetics of the island density. It is shown that experime ntal and calculated dependencies are in agreement if the mobility of island s is included. (C) 2000 Elsevier Science S.A. All rights reserved.