Surface segregation of CaF 2 in thin Si(111)/CaF 2/Si multilayers studied by total electron yield spectroscopy and in situ ellipsometry

Takeo Ejima, Katsumi Ohuchi, Makoto Watanabe

Research output: Contribution to journalArticlepeer-review


Total electron yield (TEY) measurements of a Si(111)/CaF 2 single-layer, Si( 111 )/CaF 2/Si double-layers, and Si(111)/CaF 2/Si/CaF 2 triple-layers were performed at around the Si-L edge from 0° to 80° of angles of incidence. From the resemblance of the spectrum of the Si(111)/CaF 2/Si double-layers to those of the Si(111)/CaF 2 single- and the Si(111)/CaF 2/Si/CaF 2 triple-layers and from simulations, it is suggested that the Si layer grows on the bottom CaF 2 layer and is covered with a segregated top CaF 2 layer in the present multilayers. In situ ellipsometry measurements using a He-Ne laser were also performed during epitaxial Si growth on the Si(111)/CaF 2 epitaxial film. The measured track is different from the expected curve of epitaxial Si growth, which suggests that the grown Si layer was a mixture layer of Si platelets (islands) surrounded by CaF 2. Furthermore, the track showed that the curvature changed during the Si growth, which suggests that the CaF 2 segregation has several steps during the Si growth. From the TEY and ellipsometry results, the diameter of the platelets is estimated as 20.0-100.0 nm, the diffraction effect of the light used being taken into account.

Original languageEnglish
Pages (from-to)5171-5177
Number of pages7
JournalJapanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
Issue number7 A
Publication statusPublished - 2005 Jul 8


  • Angle dependence
  • CaF
  • Ellipsometry
  • Extinction
  • In situ
  • Multilayer
  • Observation
  • Real time
  • Segregation
  • Si
  • Si-l
  • TEY
  • Total electron yield

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

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