Negative- and positive-point corona discharge oxidation processes (anodic and cathodic cases, respectively), result in markedly different oxide thickness profiles. In the cathodic case, the enhancement varies in a complex manner over the entire wafer surface. The enhancement profiles are simulated using linear-parabolic rate constants, modified to account for the corona current. Three enhancement factors are required for a reasonable fit. The interface reaction constant may be enhanced in both anodic and cathodic cases due to movement or emission of electrons. Effective oxidant concentration under the corona needle is hypothesized to be increased in the anodic case, and decreased in the cathodic case. Oxide fixed charge concentrations are much higher in the cathodic case and are potentially consistent with an electrochemical model of the oxidation rate enhancement.