Kirkendall study of electromigration in thin films

Abstract

A series of experiments has been designed to measure the effects due to solute addition on electromigration in thin films. These experiments are based on a "cross-stripe" sample geometry and in principle are similar to the Kirkendall study of bulk diffusion couples. An analysis of grain boundary electromigration is presented here to show how one can measure (a) the effect of solute addition on solvent electromigration at grain boundaries, (b) the critical solute concentration required for reducing electromigration damage and (c) the solute effective charge and diffusivity at grain boundaries. Measurements have been made for Cu in Al and for Ag in Au over a limited range of temperatures near 250°C and results are reported. Data obtained for Cu in Al are sufficiently detailed for the self-consistency of our measurements and the validity of the analysis to be examined. The overall agreement is satisfactory. © 1975.