Drift velocity experiments were performed on multicrystalline lines of the pure metal in order to determine the electromigration activation energy. Lines were analyzed which had been cut from films processed by using partially-ionized beam-deposition techniques. One set of lines was analyzed in the as-deposited condition, while others were annealed before etching. The measured drift velocities differed markedly between these 2 types of film, as did the grain-boundary character distributions which were measured by means of orientation imaging. The data were analyzed on the basis of Borisov’s equation in order to obtain mean grain-boundary energies. The grain-boundary energies of films with a poor electromigration performance were estimated to be equal to those for random boundaries. The energies of the more reliable films were calculated to be the same as those reported for twin boundaries in Al. Percolation theory was used to explain the results in terms of the proportions and connectedness of special boundaries in the films.

Electromigration Properties of Multigrain Aluminium Thin Film Conductors as Influenced by Grain Boundary Structure. O.V.Kononenko, V.N.Matveev, D.P.Field: Journal of Materials Research, 2001, 16[7], 2124-9