Preferential Sputtering of Tantalum Oxide: Reemission of Helium and Transient Effects in the Altered Layer

Samples of Ta2O5 were bombarded with 1.5 keV and 2.0 keV He+ ions at different angles of incidence until equi1ibriun surface concentration was reached as measured by Auger Electron Spectroscopy. The reemission of the implanted hel i um duri ng sputteri ng with 1 keV Ar+ ions was measured by the change of the helium partial pressure. The correlation between the depth di stri bution of the sputteri ng particles and the concentration depth profile supports the assumption that the altered layer corresponds to the range profile of the bombarding ions. Changes of the angle of i nci dence result in characteri stic transient surface concentration changes which can be explained by applying existing models for the development of the altered layer.