Atomistic Simulation of Field Enhanced Oxidation of Al (100) Beyond the Mott Potential

Molecular dynamics simulations employing dynamic charge transfer between atoms indicate a significantly enhanced rate of Al(100) oxidation by O2 and O at 300 K in the presence of an electric field. Increasing the electric field (approximately 10(7) V/cm) drives the surface chemisorbed oxygen to the vacancy sites in the oxide interior leading to dramatic density and stoichiometry improvements of the grown ultrathin oxide film. The associated oxidation kinetics enhancement due to the applied electric field is postulated to arise from the activation barrier lowering at electrostatic potentials approaching the Mott potential and beyond, leading to a dramatically increased ion migration through oxide film. The results are of significance to understanding mechanisms of early stage oxide growth as well as technologies utilizing ultrathin oxides.