Influence of electric field annealing on atom diffusion in Cu/Ta/Si stacks

In this letter, we present a quantitative analysis of the influences caused by an electric field annealing on interface atom diffusion in a Cu/Ta/Si stack at a range of temperatures 450～650 °C. The results indicate that the external electric field has a remarkably accelerated effect on Cu atom diffusion in the Ta layer and the failure of Ta as the diffusion barrier. The preexponent D ₀ and the activation energy Q for Cu atom diffusion in the Ta layer were both decreased with the application of an external electric field. The activation energy for electric field annealed stacks is 1.22 eV, which is lower than that for annealed stacks (1.58 eV). The accelerating effect is mainly attributed to the perturbation of the electric state of the defects in the interface and grain interior.