Adsorption of Oxygen on HF-Etched Si(111) Surfaces: XPS Study

Abstract

X-ray photoelectron spectroscopy studies of the Si(111) surfaces, after dilute HF etching and methanol rinse, are reported. These included a detailed analysis of the main core-levels (Si 2p, O is) and the valence band spectra. The observed asymmetry of the O is łines was attributed to two contributing subpeaks: the main (1) and the minor one (2), shifted 1.5 eV to higher binding energies. Their relative intensity was found to depend on the air exposure time and on the take-off angle. The peaks were assigned to two different positions of surface oxygen: (1) 0 chemisorbed with methoxy group, (2) bridging O atom. The valence band X-ray photoelectron spectroscopy spectra reveał the influence of surface states induced by the "chemisorbed O"-Si bond.