Visualizing the Electron Wind Force in the Elastic Regime

With continued scaling toward higher component densities, integrated circuits (ICs) contain ever greater lengths of nanowire that are vulnerable to failure via electromigration. Previously, plastic electromigration driven by the electron wind has been observed, but not the elastic response to the wind force itself. Here we describe mapping, via electron energy-loss spectroscopy, the density of a lithographically defined aluminum nanowire with sufficient precision to determine both its temperature and its internal pressure. An electrical current density of 10(8) A/cm(2) produces Joule heating, tension upwind, and compression downwind. Surprisingly, the pressure returns to its ambient value well inside the wire, where the current density is still high. This spatial discrepancy points to physics that are not captured by a classical wind force model and to new opportunities for optimizing electromigration-resistant IC design.

Automated summary

By mapping the density of an aluminum nanowire, it was discovered that an electrical current can cause Joule heating, resulting in tension upwind and compression downwind. Surprisingly, the pressure inside the wire returns to its ambient value despite high current densities, indicating new opportunities for improving IC design resistant to electromigration.