Si 2p Spectra of Initial Thermal Oxides on Si(100) Oxidized by H2O

Initial stage of wet thermal oxidation of Si(100)2×1 surfaces using water has been investigated by high-resolution Si 2p core-level measurements with synchrotron radiation at substrate temperatures of room temperature (RT) - 800 °C. Water was found to dissociatively adsorb at RT, forming Si-H and Si-OH bonds. At elevated temperatures, the four oxide components that are identical with those in dry oxidation also appeared in the spectrum in addition to the Si-H component. The Si-H component showed a peak shift toward higher binding energies with temperature, which suggests transformation from the monohydride to the dihydride at higher temperatures.