Scanning tunneling microscopy study of initial growth of CaF2 and BaF2 on Si(111)

Touru Sumiya, Tadao Miura, Haruko Fujinuma, Shun Ichiro Tanaka

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3 Citations (Scopus)


Scanning tunneling microscopy (STM) has been used to investigate nucleation and initial growth in the heteroepitaxies of calcium fluoride (CaF2) and barium fluoride (BaF2) on Si(111) surfaces in situ. The fluoride depositions and the STM measurements are performed at a substrate temperature of about 400°C. STM images clearly show that a BaF2-deposited surface has a different morphology from that of CaF2-deposited surface. Preferential nucleation and island growth of BaF2 only occur at steps and domain boundaries on a Si(111)-7 x 7 reconstructed surface. On the other hand, CaF2 islands nucleate not only at steps and domain boundaries but also in domain-boundary-free regions of a Si(111) surface. We attribute the difference in the morphologies to the much higher mobility and diffusion length of a BaF2 molecule in comparison to those of a CaF2 molecule on a Si(111) surface at 400°C. We also report the first STM measurement of a (CAF2 + BaF2)-coexisting surface at 480°C.

Original languageEnglish
Pages (from-to)L1077-L1080
JournalJapanese Journal of Applied Physics, Part 2: Letters
Issue number8 SUPPL. B
Publication statusPublished - 1996 Aug 15
Externally publishedYes


  • Barium fluoride
  • Calcium fluoride
  • Heteroepitaxy
  • Scanning tunneling microscopy
  • Silicon

ASJC Scopus subject areas

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


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