A photoelectron spectroscopy and photon stimulated desorption study of H2O on Si(100) 2×1

In English We have studied H2O adsorption on the Si(100) surface using photoelectron spectroscopy to record Si valence bands and Si 2p core level spectra; and photon stimulated desorption to record Si 2p edge total electron yield and H + -ion yield spectra. We assign the valence-band H2O induced peaks at EB=6.3 and 11.2 eV to the Si–OH and to the O–H bonds, respectively. The H2O dosed Si 2p core level spectrum exhibits two H2O induced equal intensity surface peaks with surface core level shifts of +0.25 and +1.00 eV that we assign to surface Si atoms in the Si–H and the Si–OH bonds, respectively. We interpret the features in the Si 2p edge H + -ion yield spectrum as ion desorption from SiO2 at surface defect minority sites. We conclude that H2O adsorbs dissociatively as H and OH radicals on the Si(100) 2×1 surface dimers and that there are defect minority sites on the surface where H2O adsorption causes SiO2 formation.