Comparison of initial oxidation of Si(111)7×7 with ozone and oxygen investigated by second harmonic generation

Ken Nakamura, Akira Kurokawa, Shingo Ichimura

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Initial oxidation by high purity ozone and molecular oxygen of Si(111)7×7 was investigated by second harmonic generation (SHG) with a 1.064 μm Nd:YAG laser. Decrease of second harmonics (SH) intensity to almost zero after 5 L ozone gas exposure, in spite of the fact that molecular oxygen kept SH intensity for the same amount of exposure, indicated that ozone is inserted into the Si-Si backbond in the subsurface layers more effectively than molecular oxygen. In the initial exposure, rates of rapid decrease in SH intensity for both ozone and oxygen adsorption were in the same order of magnitude, although O 1s x-ray photoelectron spectroscopy (XPS) intensity showed high reactivity of ozone. This is because of a difference in the information depth between SHG and XPS so that oxygen species in the subsurface layers are not effective in decreasing SH intensity. This indicates that the process of attacking backbonds is underway even with an initial exposure of <5 L.

Original languageEnglish
Pages (from-to)2441-2445
Number of pages5
JournalJournal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
Issue number4
Publication statusPublished - 1997 Jan 1
Externally publishedYes


ASJC Scopus subject areas

  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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