Analytical electron microscopy and Auger electron spectroscopy study of low-temperature diffusion in multilayer chromium-copper-nickel-gold thin films

Analytical electron microscopy and Auger electron spectroscopy were used to study low-temperature diffusion and segregation in multilayer Cr-Cu-Ni-Au thin films. Annealing at 573 K for 900 s leads to pronounced element redistributions between the film layers. Both Cu and Au diffuse towards each other across the Ni layer and exhibit the most intensive redistribution by the mechanism of grain boundary diffusion. The Ni layer is not effective as a diffusion barrier. Details of the measured depth profiles of Au and Cu, such as observed accumulation of the segregating Cu atoms at the Ni-Au interface and non-uniform Au and Cu enrichment of individual grains, correlate with the grain structure of film layers which affects the effective diffusion rate