MIAYKE Koji's Homepage

AIST
Research Topics

Stability and Nuclear Formation of Si(111)-7×7 Structure as Determined from Charge Redistribution in Surface Layers

Abstract
　By considering the charge transfer from adatoms to rest atoms, the structure of the dimer and stacking-fault (DS) layers in the Si(111) dimer-adatom-stacking-fault (DAS) structure was analyzed at a subunit level on a quenched surface. In comparison with the modified model of Vanderbilt, corner holes with a completed DS structure in the second layer, completed corner holes, were confirmed to play a key role not only in the mechanism to stabilize the DAS structure, but also in its formation process. The formation of the completed corner hole works as a rate-limiting process for the growth of the DAS structure. This mechanism was shown to be quite consistent with the experimental results obtained using scanning tunneling microscopy on the quenched Si(111) surface.
Results

STM image of a quenched Si(111) surface. Three 9×9 domains exist sharing corner holes with a 7×7 triangular domain.



Schematic diagram of the formation process of the DAS structure.
  1. High temperature disordered area
  2. Nucleation of a corner hole
  3. Growth of half-unit cells of DAS structures including an SF from the corner hole
  4. Complete formation of the DAS structure

References

  1. "Characteristic Structures of the Si(111)-7×7 Surface Step Studied by Scanning Tunneling Microscopy"
    K. Miyake, S. Okawa, O.Takeuchi, D.N. Futaba, K. Hata, R. Morita, M. Yamashita, and H. Shigekawa
    Journal of Vacuum Science & Technology A 14, 1549-1552 (2001).

  2. "Si(111) Surface under Phase Transitions Studied by the Analysis of Inner Layer Structures Using Bias-dependent Scanning Tunneling Microscopy"
    K. Miyake, T. Kaikoh, Y.J. Li, H. Oigawa, H. Shigekawa
    Japanese Journal of Applied Physics 38, 3841-3844 (1999).

  3. "Stability and Nuclear Formation of Si(111)-7×7 Structure as Determined from Charge Redistribution in Surface Layers"
    K. Miyake, H. Oigawa, K. Hata, R. Morita, M. Yamashita, and H. Shigekawa
    Surface Science 429, 260-273 (1999).

  4. "How the Down Step Edges Influence Formation of the 7×7 Structure of Si(111)"
    K. Hata, S. Okawa, K. Miyake, and H. Shigekawa
    Scanning 20, 398-402 (1998).

  5. "Role of Corner Holes in Si(111)-7×7 Structural Formation Studied by HBO2 Molecular Irradiation and Quenching"
    K. Miyake, M. Ishida, K. Hata, and H. Shigekawa
    Physical Review B 55, 5360-5363 (1997).

  6. "Quenched Si(111)-DAS (dimer-adatom-stacking fault) Structures Studied by Scanning Tunneling Microscopy"
    K. Miyake, M. Ishida, M. Uchikawa, K. Hata, H. Shigekawa, Y. Nannichi, and R. Yoshizaki
    Surface Science 357-358, 464-467 (1996).

  7. "Electronic Structure of Si(111)-7×7 Phase Boundary Studied by Scanning Tunneling Microscopy"
    K. Miyake, H. Shigekawa, and R. Yoshizaki
    Applied Physics Letters 66, 3468-3470 (1995).