Oxidation of H-covered flat and vicinal Si(111)-1×1 surfaces

The initial stages of O2 oxidation of H-passivated flat and vicinal Si(111) surfaces are investigated by monitoring the Si–H stretch vibrations with infrared absorption spectroscopy. We find that the incorporation of oxygen into silicon is activated (1.66±0.10 eV on flat surfaces), involving a multistep process. Oxygen molecules are incorporated into Si–Si bonds without removing surface hydrogen and this process is facilitated at steps.