High-resolution photoemission studies of the interfacial reactivity and interfacial energetics of Au and Cu Schottky barriers on methyl-terminated Si(1 1 1) surfaces

Ralf Hunger, Rainer Fritsche, Bengt Jaeckel, Lauren J. Webb, Wolfram Jaegermann, Nathan S. Lewis

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20 Citations (Scopus)

Abstract

The Schottky junction formation by the stepwise evaporation of gold and copper, respectively, onto methyl-terminated silicon, CH3-Si(1 1 1), was investigated by synchrotron X-ray photoelectron spectroscopy. During the junction formation process, interface reactions occurred as revealed by the appearance of chemically shifted Si 2p components. Upon deposition of Au, the formation of about one monolayer of gold silicide, SiAu3, with a Si 2p chemical shift of +0.75(2) eV, was observed. The SiAu3 floated on top of the growing gold layer. Similarly, for the deposition of Cu, the methyl termination layer was partially disrupted, as indicated by the appearance of a -0.28(2) eV chemically shifted Si 2p component attributable to an interfacial copper silicide phase, SiCu3. Hence, the termination of the Si(1 1 1) surface by methyl groups did not completely prevent interfacial reactions, but did reduce the amount interfacial reaction products as compared to bare Si(1 1 1)-(7 × 7) surfaces. Electron Schottky barrier heights of 0.78(8) eV (Au) and 0.61(8) eV (Cu) were measured. Within the experimental uncertainty the observed Schottky barriers were identical to those ones obtained on non-passivated, (7 × 7)-reconstructed Si(1 1 1) surfaces. Thus, the modification of the electronic properties of the silicon-metal contact requires the complete absence of interfacial reactions.

Original languageEnglish
Pages (from-to)2896-2907
Number of pages12
JournalSurface Science
Volume601
Issue number14
DOIs
Publication statusPublished - Jul 15 2007

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Keywords

  • Alkanes
  • Copper
  • Gold
  • Metal-semiconductor interfaces
  • Schottky barrier
  • Silicides
  • Silicon
  • Synchrotron radiation photoelectron spectroscopy

ASJC Scopus subject areas

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

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