The concentration profile in binary A–B nm-scale multi-layers exposed to thermal annealing was calculated based upon the Martin kinetic discrete model for one-dimension nonlinear interdiffusion by a diffusion asymmetry coefficient m′ and an ordering energy V between A and B atoms. With decreasing the diffusion asymmetry coefficient m′ from 0 to -6, the concentration profile of the multi-layers deviated from symmetrical distribution, and their interfaces became sharp and shifted towards the side of the sub-layer with lower pair interaction energy. The difference of diffusion coefficient of A and B atoms caused by the diffusion asymmetry coefficient m′ led to the difference of net fluxes of A and B atoms in

the multi-layers. When the ordering energy V changed from -0.001 to -0.05eV, change in the concentration profile and interface structure was same for the multi-layers with a given diffusion asymmetry coefficient m′, but the calculated diffusion time decreased correspondently. The lower ordering energy V made the A and B atoms aggregating more easily during the interdiffusion. It was found that the non-linear interdiffusion of a series of binary nm-scale multi-layers could be characterized by the diffusion asymmetry coefficient m′ and the ordering energy V, to explore the solid state reaction between the sub-layers of nm-scale multi-layers.

Nonlinear Interdiffusion in Binary Nanometer-Scale Multilayers Submitted to Thermal Annealing. B.S.Cao, M.K.Lei: Thin Solid Films, 2008, 516[8], 1843-8