Activation energy enhancement during initial silicon-oxide growth in dry oxygen

Silicon oxidation enhancement in the thin oxide region is investigated by studying activation energy dependence on SiO2 thickness using the Arrhenius plot of oxidation rates. The enhancement of the activation energy is found to occur at approximately 30 Å SiO2 thickness. The change of the oxidation-limiting process from surface reaction enhancement to oxidant diffusion retardation can provide an explanation of this activation energy enhancement. This model also provides a consistent view of previous experiments in the thin region.