Thermal nitridation of the Si(111)-(7×7) surface studied by scanning tunneling microscopy and spectroscopy

C. L. Wu, J. L. Hsieh, H. D. Hsueh, S. Gwo

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33 Citations (Scopus)

Abstract

By-using scanning tunneling microscopy and spectroscopy (STM and STS), the initial stages of NH3 exposure on Si(111)-(7×7) at different substrate temperatures and dosages have been studied. At room and very high (∼1050 °C) temperatures, the 7×7 surface structure remains and the nitrided sites appear darker, randomly distributing on the surface. Moreover, we find a constant ratio (∼3.46-3.83) of reacted center adatoms to reacted comer adatoms on the partially nitrided surfaces. At intermediately temperatures (∼900 °C), the majority (>90%) of the reacted surface forms the well-ordered silicon nitride 8×8 reconstruction. In this regime, hexagonal- and triangular-shaped nitride islands can be observed on the 8×8 and 7×7 surfaces, respectively. We have also used STS to investigate the changes of local density of states on the nitrogen-reacted 7×7 surfaces prepared by different conditions.

Original languageEnglish
Article number045309
Pages (from-to)453091-453096
Number of pages6
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume65
Issue number4
Publication statusPublished - 2002 Jan 15

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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