Oxidation mechanism of the ammonium-fluoride-treated Si(100) surface

Journal Article · Fri Nov 01 04:00:00 EST 1996 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.362727· OSTI ID:385644

Kluth, G J; Maboudian, R ^[1]

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1. Department of Chemical Engineering, University of California, Berkeley, California 94720 (United States)

High-resolution electron energy loss (HREEL) spectroscopy, Auger electron spectroscopy, and low-energy electron diffraction have been employed to examine the initial oxidation stage of ammonium-fluoride-treated Si(100) surfaces exposed to air. The NH{sub 4}F treatment results in a hydrogen-terminated surface, as shown by the presence of the Si{endash}H stretch (2100 cm{sup {minus}1}), SiH{sub 2} scissor (910 cm{sup {minus}1}), and SiH bend (650 cm{sup {minus}1}) in the HREEL spectra. Initial oxidation on this surface occurs through oxygen insertion in the silicon backbonds, as indicated by the presence of the asymmetric bridge-bonded oxygen stretch in the region between 1060 and 1160 cm{sup {minus}1}. Oxygen is observed in both surface and bulk bridge-bonding sites for even the shortest air exposures, suggesting that initial oxygen uptake is not taking place in a layer-by-layer fashion. Auger electron spectroscopy shows a slow uptake of oxygen over the first few days of air exposure, followed by more rapid oxidation. Over the first two weeks of air exposure, the Si{endash}H stretch at 2100 cm{sup {minus}1} gradually disappears, accompanied by the appearance of oxygen backbonded Si{endash}H peaks around 2250 cm{sup {minus}1}. This behavior indicates that, despite the increase in oxygen uptake, the hydrogen termination remains intact, and further confirms that oxygen uptake occurs through insertion in the silicon backbonds. Water is found to play a significant role in the initial oxidation. {copyright} {ital 1996 American Institute of Physics.}

• OSTI ID: 385644
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 9 Vol. 80; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AES
AMMONIA
AUGER ELECTRON SPECTROSCOPY
EEL SPECTROSCOPY
ELECTRON DIFFRACTION
ETCHING
FLUORINE
OXIDATION
SILICON
SURFACE TREATMENTS
SURFACES