A rate-equation model for the growth of metallic thin films in ion beam assisted deposition

Abstract

We describe a simple and fast rate-equation model for surface growth during ion beam assisted metal-on-metal deposition. In terms of the rate coefficients the model describes how island detachment and breakup, adatom diffusion and interlayer transitions of adatoms affect the growth. Results from our model can be directly compared to experimental data, also for coverages of several layers. We identify parameter values corresponding to different modes of growth and locate the phase boundary between them as a function of temperature. We also show that in ideal layer-by-layer growth island size distributions retain the regular scaling form. Our model shows that in order to obtain thin films of good quality, both efficient detachment of adatoms and sufficiently fast interlayer transitions are needed. The results validate the approximations made in an earlier, more coarse-grained model.