Ni diffusion in Cu 6Sn 5 intermetallic compound was investigated. First, we successfully fabricated preferred-orientation Cu 6Sn 5 crystal by liquid-phase electroepitaxy (LPEE). Then, Ni/Cu 6Sn 5 diffusion couples were produced by sputtering from a Ni thin film onto the Cu 6Sn 5 crystal. Ni/Cu 6Sn 5 diffusion couples were annealed at different temperatures of 120°C, 160°C, 200°C, 255°C, 290°C, and 320°C for 2 h in a vacuum. The Ni atomic profile across the Ni/Cu 6Sn 5 interface was obtained by electron spectroscopy for chemical analysis (ESCA). From the Ni atomic profiles, the Matano method was used to evaluate the Ni interdiffusion coefficients (D Ni) in the Cu 6Sn 5 crystal obtained with different annealing temperatures, which then yields the activation energy for Ni diffusion in the Cu 6Sn 5 crystal at a particular Ni content. We found that, as Ni diffuses in the ternary Cu 6-x Ni x Sn 5 compound phase, the activation energy of Ni interdiffusion decreases with the Ni content.
- Activation energy
- interdiffusion coefficient