Oxidation at low temperatures

The growth of oxide films on metals and semiconductors at low temperatures was not adequately explained until Mott proposed electron tunnelling as the mechanism of charge neutralization. This led to the Cabrera-Mott model of oxidation in which a self-induced field reduces the activation energy for ion movement. The resulting equation was shown by Fehlner to fit the oxidation kinetics when network-forming oxides can grow. The present work examines kinetic data for network modifiers and attempts to fit them to a direct logarithmic expression of Uhlig. Trapped charge is assumed to limit electron transfer. Charge densities in the 10 18 −10 20 cm −3 range are found for Cu, Na, Be, Zn, and Fe.