Investigations of the SiO2/Si interface. I. Oxidation of a clean Si(100) surface using photoemission spectroscopy with synchrotron radiation

The surface oxidation process of Si(100), and the distribution of intermediary oxidation states at the SiO2/Si interface have been extensively studied by high resolution (ΔE<0.3 eV) photoemission spectroscopy using synchrotron radiation. The results show that the ratio at the SiO2/Si interface for three intermediary states, Si3+, Si2+, and Si1+ (SiOx), is strongly dependent on SiO2 layer thickness. In particular, the proportion of Si3+ increases with the formation of the 0∼1 nm thick SiO2 layer. However, the three intermediary components at the interface are distributed with ratios of Si3+:Si2+:Si1+=7:2.5:1 in the oxidation stage where a SiO2 layer is formed over 1 nm.