Mass transport during electromigration in aluminum-magnesium thin films

Abstract

Single-crystal and polycrystalline aluminum thin film conductors, containing up to 6 at.% magnesium, were subjected to electromigration experiments at 175° and 225°C with current densities up to 4 × 106 A/cm2 and for times up to 50 000 h. These conductors were subsequently examined in order to obtain quantitative data on mass transport during electromigration. The results indicate that in an alloy containing about 6 at.% magnesium the lattice diffusivity of aluminum is larger by an order of magnitude than the corresponding lattice diffusivity in pure aluminum, whereas the grain boundary diffusivity of aluminum in this alloy is two orders of magnitude smaller than the corresponding value in pure aluminum. Further, the lattice and grain boundary diffusivities of magnesium in this alloy are of the same order of magnitude as the aluminum diffusivities, and appear to be slightly smaller in both cases. © 1975.