Surface phase transformations in the Ni/Si(111) system observed in real time using low-energy electron microscopy

Peter Bennett, M. Y. Lee, S. A. Parikh, K. Wurm, R. J. Phaneuf

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Abstract

Submonolayer Ni deposits quenched from above 840 °C produce an “impurity stabilized” 1×1 phase, which scanning tunnel microscope observations reveal to be A1×1 lattice gas of ring clusters (RCs) together with Si adatoms in local 2×2 domains. We call this phase 1×1-RC. Real time low-energy electron microscopy observations show the following: Terraces are covered with the 1×1-RC phase except for narrow strips of 7×7 along the top side of bilayer steps. The strip width decreases with increasing Ni coverage and increasing quench rate. Slow cooling results in clean 7×7 only. Depositing Ni at 700 °C causes the IX 1-RC phase to expand, consuming 7×7. At 720 °C, the 1 Xl-RC phase mixes with 7×7 to cover the terraces uniformly. Depositing at 500 °C instead causes formation of NiSi2 islands in a matrix of clean 7×7. These reactions are summarized in terms of a temperature versus coverage phase formation diagram.

Original languageEnglish (US)
Pages (from-to)1728-1732
Number of pages5
JournalJournal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
Volume13
Issue number3
DOIs
StatePublished - May 1995

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ASJC Scopus subject areas

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

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