Electromigration-induced dislocation climb and multiplication in conducting lines

Abstract

Electromigration along dislocation cores is considered as a mass-transport mechanism, in conducting lines of bamboo-like grains, below one half of the melting temperature. Given that the dislocation density in annealed metals may be insufficient to account for the observed mass-transport rate, this paper focused on electromigration-induced dislocation motion and multiplication. A prismatic loop climbs like a rigid ring, as electromigration relocates atoms along the core, from one portion of the loop to the other. Each loop is therefore a mass carrier: a vacancy loop migrates towards the cathode and an interstitial loop towards the anode. Furthermore, a thread of an edge dislocation multiplies prismatic loops under a sufficiently high electric field. A bamboo grain-boundary catches loops on one side and emits on the other. Available empirical facts are discussed according to this picture, including lifetime, linewidth, stress gradient and alloying.