Films of Nb on Ti, and films of Ti on Nb, were prepared by means of electron beam deposition or radio-frequency magnetron sputtering. The specimens were heated in vacuum, and migration through the films was monitored by means of Auger electron spectroscopy. In the case of electron-beam deposited films, it was found that Ti diffused very rapidly through the Nb film; with 60% of the activation energy for bulk diffusion. The Nb did not diffuse through the Ti film with any degree of rapidity. A similar behavior was found for sputter-deposited films. The diffusion coefficient was calculated by using the film thickness as the diffusion distance. It was found that the results could be described by:

D (cm2/s) = 1.4 x 102 exp[-53.8(kcal/mol)/RT]

M.Yoshitake, K.Yoshihara: Journal of the Japan Institute of Metals, 1992, 56[1], 89-95