Investigation of the SiO2/Si interface. II. Oxidation of an HF-cleaned Si(100) surface using photoemission spectroscopy with synchrotron radiation

The oxidation of a Si(100) surface cleaned using a HF solution and exposed to air, and the composition of the SiO2/Si interface are studied in situ by high resolution (ΔE<0.3 eV) photoemission spectroscopy, using synchrotron radiation. The results are compared with those of a Si(100) surface cleaned by repeated Ar ion sputtering and annealing. The presence of SiC and SiH bonding states at the SiO2/Si interface for the HF-cleaned Si restricts oxidation—the diffusion of oxygen atoms into the Si substrate. In the results, the proportions of Si2+ and Si3+ intermediary states at the interface increase and the interface broadens (0.85–1.0 nm), compared with the oxidation of the clean Si(100) surface.