Positron lifetime measurements were performed on thin films in order to identify lattice defects. Theoretical positron lifetimes of vacancy clusters of Cu were also calculated for identification of the experimental values. Cu thin films were prepared by electrochemical deposition and physical vapour deposition. All of the Cu thin films had longer positron lifetimes than bulk Cu did. This indicated that lattice defects were introduced during deposition. However composition analysis of positron lifetimes showed that whereas vacancy clusters exist in the electrochemically deposited Cu thin film, the positron lifetime of defect component in the physical vapour deposited Cu thin films was shorter than that of mono-vacancy. On the other hand, the positron lifetime of mono-vacancy was detected in physical vapour deposited Cu-0.5at%Sb thin film prepared by physical vapour deposition. In order to elucidate the effect of Sb, first-principles calculations were performed for Cu including Sb and mono-vacancy. The results suggested that mono-vacancies were introduced because of the binding energy between a Sb atom and mono-vacancy.

Identification of Lattice Defects in Cu Thin Films by Positron Annihilation Spectroscopy. M.Mizuno, T.Kihara, H.Araki, Y.Shirai, T.Onishi: Physica Status Solidi C, 2007, 4[10], 3550-3