A study has been made of the nucleation and growth of thin microcrystalline
films of Cu,Au,Pt,Ni prepared by ion-beam sputtering. In-situ measurements of
the film resistance during deposition have been analysed in terms of percolation
theory for the early, discontinuous, phase and thin film, grain boundary,
scattering for the quasi-continuous phase. This analysis yields values of the
percolation threshold, fractional coverage and lateral grain dimensions, for
different deposition rates, which are compared with the corresponding values
obtained from direct observations and soft X-ray multilayers reflection spectra.
The minimum thickness of the metallic nuclei is shown to be four atom layers.