Three-dimensional atom probe investigation of Co/Al thin film reaction
The reactive interdiffusion of Co/Al bi-layers is investigated by means of atom probe tomography. The samples are prepared by deposition of corresponding materials onto W substrate tips with a radius of curvature of ?50 nm. Nucleation of Al9Co2 phase particles is detected only after reaching a critical concentration gradient of ?0.3 nm?1 at the interface. The fast growth of the particles before the formation of a dense layer is explained by atomic transport through the incoherent interphase boundary. After consumption of the remaining pure Al, B2-ordered AlCo is detected as a second product phase.
thin film atom probe tomography reactive diffusion