Chemical composition of the SiO2/InSb interface as determined by x-ray photoelectron spectroscopy

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Abstract
The chemical composition of the interface formed between deposited SiO2 films and single‐crystal InSb substrates is investigated using high‐resolution x‐ray photoelectron spectroscopy (XPS) in conjunction with a relatively benign chemical depth‐profiling technique. The SiO2 films are deposited by the thermal decomposition of silane in the presence of oxygen in a chemical‐vapor‐deposition (CVD) reactor. Thermal oxidation of the InSb occurs in the reactor resulting in an In‐rich oxide and elemental Sb at the native oxide/InSb interface. The native oxide was found to be primarily composed of In2O3 and Sb2O3 in a 3:1 ratio. Reduction of the native oxide by silane forms a thin layer of elemental In at the SiO2/native oxide interface. These results are derived from intensity analysis of XPS spectra and are consistent with thermodynamic considerations.