FIGURE 41 Comparison of normal and secondary (discontinuous coarsening) grain growth in a thin film: (a) stages of grain size distribution in the two cases; (b) secondary grain growth of orientations with minimum surface energy. From Thompson.⁷¹ Reprinted with permission.

preferentially to grain boundaries without appreciable adverse effect on the electrical conductivity of the interconnect. There is independent evidence that solute enrichment at grain boundaries increases markedly as a function decreasing solid solubility.⁷⁴ A striking reduction in grain boundary diffusivity by solute segregation was described in an earlier section relative to the marked improvement in oxidation resistance of a cobalt-chromium alloy by yttrium ion implantation.