An investigation into the links between island patterns and the mechanisms of thin film deposition

Statistical analysis of pictures of island arrays grown on a substrate during thin-film deposition can yield useful information to the experimentalist such as the shape of the island size distribution. We present an investigation of how this type of information can in turn be used to identify the most important mechanisms governing the growth process. We have used a computational model based on deposition, diffusion, and aggregation (DDA) for the following situations: (1) normal DDA where the island size distributions scale with coverage and are distinguished by the critical island size; (2) DDA plus monomer evaporation, which yields scaling island size distributions that lie between a powerlaw and the normal DDA results depending on the evaporation rate; (3) DDA with a finite probability of islands absorbing monomers, which yields similar distributions to case (2) but crucially does not display the scaling with coverage; and (4) DDA with mobile islands where an even more dramatic departure from scaling is observed.