Negative ion yield and sputter yield variations for Cs+ bombardment of Si with O2 gas flooding

Klaus Franzreb, Peter Williams

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


We have investigated whether negative secondary ion yields from Cs + sputtered silicon might be improved by simultaneous O2 gas flooding, which lowers the sputter yield of the silicon, and thus, might increase the cesium content at the surface. The composition at the sputtered surface is derived from quantitative measurements of the ratios of O/Si and Cs/Si in the total emitted flux using the recently developed oxygen 18 method1 and sputter yield measurements, respectively (with XSi + X Cs + XO = 1). The silicon sputter yield, Y, is lowered by adsorbed oxygen by as much as a factor of 2.7 and is found to scale almost linearly with the silicon atom fraction XSi at the surface, resulting in the cesium atom fraction XCs at the surface remaining nearly constant during oxygen flooding. We find that oxidation of the cesiated silicon surface influences differently the useful ion yields (ions detected/atom sputtered) of various elements. The yields of B- and Cs- are enhanced by factors of 3 and 34, respectively, the yield of O- remains roughly constant, and yields of other elements (As-, Cl -, P-, Sb-, Si-) are lowered by a factor of 2 or 3.

Original languageEnglish (US)
Pages (from-to)129-133
Number of pages5
JournalSurface and Interface Analysis
Issue number1-2
StatePublished - Jan 2011


  • cesiation
  • ion enhancement
  • oxidation
  • silicon
  • sputter yield
  • useful ion yield

ASJC Scopus subject areas

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


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