MECHANISMS OF FILM GROWTH-RATE ENHANCEMENT IN ANODIC AND CATHODIC CORONA-DISCHARGE OXIATION PROCESSES

Negative- and positive-point corona discharge oxidation processes (ano dic and cathodic cases, respectively), result in markedly different ox ide thickness profiles. In the cathodic case, the enhancement varies i n a complex manner over the entire wafer surface. The enhancement prof iles 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 elec trons. Effective oxidant concentration under the corona needle is hypo thesized to be increased in the anodic case, and decreased in the cath odic case. Oxide fixed charge concentrations are much higher in the ca thodic case and are potentially consistent with an electrochemical mod el of the oxidation rate enhancement.