On the mechanism of bombardment-induced oxygen redistribution at ZrO2 surfaces

Yttria-stabilized (100) ZrO2 crystal surface was bombarded with 10-keV He+ ions. The surface compositional changes and oxygen redistribution after the bombardment were studied using XPS. O/Zr and O/Y concentration ratios were measured as a function of the photoelectron's emission angle. Oxygen enrichment at the surface and oxygen depletion in the subsurface region were established. The Zr3+ and Zr4+ valence states content was estimated after the bombardment,as well as their distribution as a function of the photoelectron emission angle. Using the influence of the carbon coverage on the signal intensify as a reference, the depth profile was estimated from all bulk elements - Zr, Y, O. The O peak at the surface was probably near-threshold sputtering in combination with chemically-driven O-trapping by the lower oxidized states of Zr in the surface region. Copyright (C) 1996 Published by Elsevier Science Ltd