Texture evolution and mechanical properties of ion-irradiated Au thin films Original Research Article

Microstructure control of thin films is of particular importance for improving the reliability of microdevices in terms of electromigration, fatigue damage and hillocking. High-energy ion bombardment has turned out to be an appropriate modification instrument as it leads to selective grain growth, resulting in single-crystal-like structures. The current work addresses the effect of 7 MeV Au+ and 1.5 MeV N+ irradiation at high fluences (up to 45 × 1016 ions cm−2) on the microstructure and the mechanical properties of 500 nm Au thin films of small initial grain size (70–90 nm). The following microstructure changes were observed: selective grain growth, texture changes, sputtering, interfacial degradation, formation of geometrically necessary dislocations, and defect clusters. Hardening behavior was found to be a consequence of grain growth (Hall–Petch effect) and the formation of ion-induced defects.