Initial oxidation states on Si(0 0 1) surface induced by translational kinetic energy of O2 at room temperature studied by Si-2p core-level spectroscopy using synchrotron radiation

Initial oxidation states on Si(0 0 1) surfaces caused by the translational kinetic energy (Et) of O2 at room temperature have been studied by the Si-2p core-level spectroscopy using synchrotron radiation. From the results of oxygen coverages as a function of the translational kinetic energy of O2 studied by the O-1s photoemission spectroscopy, it was found that there were potential energy barriers at Et=1.0 eV corresponding to the backbond oxidation of the top-layer Si atoms and at Et=2.6 eV associated with the oxidation between the second and the third Si layer. The relation between oxidation states (Si1+, Si2+, Si3+ and Si4+) and the translational kinetic energy of O2 were investigated by the high-resolution Si-2p core-level spectroscopy.