In sputtering depth profiles of metal overlayers on silicon the metal signal decays exponentially beyond the metal-silicon interface. We have investigated the effect of oxygen on decay lengths for overlayers of carbon and eight metals (Mg, Ca, Ti, Cu, In, Ag, Au, Pb) on silicon. Typically, decay lengths for electropositive metals (Ca, Mg) decrease and those for electronegative metals (Cu, Ag, Au, Pb) increase in the presence of oxygen. The results are consistent with a model in which dilute impurities segregate towards or away from the oxygenated ion-bombarded surface depending on whether they form stronger, or weaker, bonds with oxygen than does silicon.
ASJC Scopus subject areas
- Nuclear and High Energy Physics