Electromigration stress induced deformation mechanisms in free-standing platinum thin films

We present experimental evidence of anomalously high grain boundary mobility in 3–5 nm grain size platinum films at near room temperature. This mobility can be explained in terms of the localized electromigration stresses of the order of a few GPa that we observed. In the absence of conventional deformation mechanisms, the stress is relaxed through rapid grain growth up to a grain size of 40 nm. For larger grain sizes, grain boundary mobility is reduced as the stresses are relaxed by grain rotation and dislocation-based deformation mechanisms.