LAUSR

This study presents results showing that oxygen adsorption can significantly affect the morphological evolution of silver island films epitaxially grown on Si(100) and Si(111) substrates. The effects of oxygen adsorption are characterized by analyzing the morphologies formed during the thermal annealing of the island films under different annealing gas compositions. Silver island films are shown to evolve into an isotropic spherical shape in the presence of oxygen, suggesting that oxygen adsorption decreases the surface energy anisotropy of silver, which is supported by our density function theory calculation results. Oxygen is also observed to enhance the rate of dewetting and coarsening of the films, leading to a smaller areal coverage and smaller number density of silver particles. This is explained by the decrease in the activation barrier for the surface diffusion of silver adatoms and their clusters on silver and silicon surfaces with chemisorbed oxygen.