Initial stage of adsorption for organic carbons and native oxide growth on Si wafer

The adsorption of the organic carbon floating in the water on Si surface was examined by adding the polyethelpolyole into the ultrapure water wherein total organic carbon TOC.is smaller than 5 ppb. AFM and XPS measurements strongly indicate that the adsorption of the organic carbon on the Si surface has a close relationship with the native oxide growth. The relationship between the C1S integral intensity and the TOC agrees to that between the oxide thickness and the TOC for some types of wafers. The adsorption of organic carbons is affected by the electron concentration of the Si wafer. In other words, it is affected by the field-enhanced oxidation. The new model for the adsorption of the organic carbon, which assumes the field-enhancement due to the Coulomb’s force was discussed. The organic carbons which are floating near the Si surface easily adsorb to the Si surface, because the oxygen ions of the covalent bond in the organic carbons are pulled by the Coulomb’s force between the donor ions of the Si surface depleted layer and the oxygen negative ions. q2000 Elsevier Science B.V. All rights reserved