Anomalous enhancement of negative sputtered ion emission by oxygen

Peter Williams, Charles A. Evans

Research output: Contribution to journalArticle

78 Scopus citations

Abstract

Enhancement of negative sputtered ion yields by oxygen (either O+2 bombardment or O2 gas with Ar+ bombardment) is demonstrated for Si-, As-, P-, Ga-, Cu- and Au-, sputtered from a variety of matrices. Because oxygen also enhances positive ion yields of the same species, this effect cannot be simply explained on the basis of existing sputtered ion emission models. To rationalize these phenomena, a surface polarization model is developed which invokes localized electron emissive or electron retentive sites associated with differently oriented surface dipoles in the oxygenated surface. Such sites are considered to dominate the emission of negative and positive ions respectively. The model is shown to correctly predict that Au+ and Au- ion yields are much more strongly enhanced by oxygen in dilute Au-Al alloys than in pure gold.

Original languageEnglish (US)
Pages (from-to)324-338
Number of pages15
JournalSurface Science
Volume78
Issue number2
DOIs
StatePublished - Dec 1 1978
Externally publishedYes

ASJC Scopus subject areas

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

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