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.