A new technique to study the stages of oxidation of metals using oxidation induced changes in the shape of secondary ion energy spectra

Abstract

A new technique to study the oxidation process in metals based on the yield variation with oxygen dose of secondary ions whose ejection mechanisms are identified with distinctly different dynamical sputtering processes is presented. When applied to a polycrystalline copper sample the method identifies four possible oxidation stages, from adsorption into the surface layer for doses up to about 10 4L, followed by a rapid reconstruction to a Cu 2O structure at 10 4L, followed by a slow growth of bulk oxide up to 10 4L and a further physisorption of oxygen or transition to a surface CuO structure at higher doses. The technique provides a significant increase in the versatility and usefulness of SIMS equipment incorporating appropriate energy analysis facilities.