Relaxation phenomenon during electromigration under pulsed current

Abstract

Relaxation in electromigration is one of the most important factors which determine the lifetime of a conductor carrying a pulsed current. The purpose was to clarify the mechanism of this relaxation. During low-frequency (DC to mHz) pulse-migration tests, an extremely slow relaxation was detected in Al conductor resistances after pulse-on and pulse-off. Conductor lifetime dependence on the pulse frequency revealed that this relaxation phenomenon corresponds to the recovery of migration damage. The very slow rate of the relaxation suggests that the resistance changes are caused by processes such as long-distance grain boundary diffusion.<>