Electromigration Lifetime of Penta-Twinned Gold Nanowires: Implications for Flexible Electronics

Metallic nanowires have a wide range of potential applications as interconnects in next-generation electronic devices, such as flexible electronics, due to their excellent electrical and mechanical properties. However, for their successful application, it is necessary to assess their electrical reliability, namely, their behavior under electromigration, a common failure mode for electronic interconnects. Here, for the first time, we have experimentally characterized the electromigration reliability of individual penta-twinned gold nanowires, conducting time-to-failure tests for 30 samples as a function of temperature. At each temperature, the distribution of results was modeled with a log-normal distribution to find the median time to failure (MTTF), an important metric for interconnects. The electromigration activation energy and other relevant constants were then determined by fitting the MTTF results to the classic Black's electromigration model. The activation energy found (0.47-0.58 eV) suggests that surface diffusion is a significant contributor to electromigration, which indicates that further improvements in lifetime and reliability could be obtained by surface passivation of the nanowires' surface.