THE EFFECT OF A MODULATED FLUX ON THE GROWTH OF THIN-FILMS

Thin films are usually obtained by depositing atoms with a continuous flux. We show that using a chopped flux changes the growth and morphol ogy of the film. A simple scaling analysis predicts how the island den sities change as a function of the frequency of the chopped flux in si mple cases where aggregation is irreversible. These predictions are co nfirmed by computer simulations. We show that the model can be used to obtain information on the diffusion or evaporation of the adatoms. Th e model is also useful for understanding the growth of thin films prep ared by pulsed sources. (C) 1997 Elsevier Science B.V.