Nucleation and growth of thin films: recent progress

Abstract

Progress in understanding the three growth modes of crystal growth and surfaces is briefly reviewed. Island growth typically has small critical nucleus sizes (i=1 frequently) and adsorption, diffusion and cluster binding energies can be abstracted from comparison of kinetic models with electron microscope experiments. Recent work which extends this approach to include cluster mobility, defect induced nucleation and alloy films is cited. Recent work on the layer-plus-island, or Stranski-Krastanov growth mode, using an ultra-high vacuum scanning electron microscope and several related surface techniques to study the growth of silver on several metal and semiconductor surfaces, is highlighted. It is shown that typically i ∼ 10 and binding energies of small clusters on metal surfaces are much less than expected on simple pair-bond models. These ideas can be extended to layer growth, but experimental work has been hampered by lack of suitable surface sensitive microscopic techniques. Some comments on the potential use of RHEED and reflection microscopy, and predictions for the nucleation densities expected in layer growth of semiconductors and metals, are made.