Site seectivity in the initial oxidation of the Si(111)-7 X 7 surface

Jeong Sook Ha, Kang Ho Park, El Hang Lee, Seong Ju Park

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

The site selectivity of oxygen in the initial oxidation of the Si(111)-7 X 7 surface was investigated using a scanning tunnelling microscope. At room temperature, two different oxygen-induced features, bright and dark sites, were observed indicating two different oxygen chemisorption configurations. In particular, the major dark features were observed preferentially at the center adatom sites of the faulted half of the dimer-adatom-stacking-fault (DAS) structure over corner ones, which is different from previous results. We explain this in terms of the difference in the potential energy curves of two sites combined with the effect of the slow oxygen exposure (1 × 10 -9 Torr) that we used. At low oxygen pressure, oxygen atoms have sufficient diffusion time to be adsorbed on the most stable sites. This proposal is supported by the pressure dependence of the site selectivity that we measured. Furthermore, when the sample was exposed to oxygen at high temperatures, the dark features still preserved the strong site preference on the center adatom sites supporting both our hypothesis and the previously reported idea that center adatom sites are thermally more stable than the corner ones.

Original languageEnglish
Pages (from-to)317-322
Number of pages6
JournalApplied Surface Science
Volume126
Issue number3-4
DOIs
Publication statusPublished - 1998 Apr
Externally publishedYes

Keywords

  • Microscope
  • Oxidation
  • Scanning tunnelling
  • Si(111)-7 x 7
  • Site selectivity
  • Thermal stability

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Physics and Astronomy(all)
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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