ON THE DIRECTION OF ELECTROMIGRATION IN THIN SILVER, GOLD, AND COPPER FILMS

Abstract

Migration of ions in thin silver, copper, and gold films under the influence of a direct current has been found to be directed towards the cathode, contrary to observations in bulk metals. This was concluded from resistance and radioactive tracer measurements as well as scanning electron micrographs. The results can be explained by using the concept that electromigration in thin films is confined to grain boundaries, and the electron concentration in the grain boundary is different from that in the bulk.