Simultaneous observation of oxygen uptake curves and electronic states during room-temperature oxidation on Si(0 0 1) surfaces by real-time ultraviolet photoelectron spectroscopy

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Abstract

Ultraviolet photoelectron spectroscopy was used to measure the oxygen uptake, changes in work function due to the surface dipole layer of adsorbed-oxygen atoms, Δφ{symbol}SDL, and changes in band bending due to the defect-related midgap state, ΔBB, simultaneously during oxidation on Si(0 0 1) surface at room-temperature, RT, under an O2 pressure of 1.3 × 10-5 Pa. The oxygen dosage dependence of Δφ{symbol}SDL revealed that dissociatively adsorbed-oxygen atoms occupy preferentially dimer backbond sites at the initial stage of Langmuir-type adsorption, which is associated with a rapid increase of ΔBB. When raising temperature to ∼600 °C, such preferential occupation of the dimer backbond sites by oxygen atoms is less significant and ΔBB becomes smaller in magnitude. The observed relation between Δφ{symbol}SDL and ΔBB indicates that point defects (emitted Si atoms + vacancies) are more frequently generated by oxygen atoms diffusing to the dimer backbond sites at lower temperature in RT -600 °C.

Original languageEnglish
Pages (from-to)3838-3842
Number of pages5
JournalSurface Science
Volume601
Issue number18
DOIs
Publication statusPublished - 2007 Sep 15

Keywords

  • Oxidation
  • Point defect generation
  • Real-time monitoring
  • Si surface
  • Strain
  • UPS

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Condensed Matter Physics
  • Surfaces and Interfaces

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