Anomalous bonding in SiO₂at the SiO₂-Si interface

Ultraviolet photoelectron spectroscopy valence-band spectra measured at 51 eV for a series of thin oxide layers thermally grown on Si(l 11) and Si(100) surfaces show that anomalous bonding configurations exist in SiO2near the interface. A comparison with theoretical density-of-states calculations indicate that these configurations cannot be related to the existence of a strained SiO2layer with a distribution of Si-O Si bond angles different to what is found in bulk SiO2. The results support the existence of threefold-coordinated oxygen centres as described in the valence-alternation-pair model. © 1987 Taylor & Francis Group, LLC.