Microstructure and electronic properties of Cu/Mo multilayers and three-dimensional arrays of nanocrystalline Cu precipitates embedded in a Mo matrix

Nanostructured Cu/Mo multilayers were prepared by magnetron sputtering. The thickness of the Cu layer was kept constant at 0.6 nm, while the thickness of the Mo layers varied from 2.5 to 20 nm for different specimens. The Cu layers exhibit a body centered cubic (bcc) structure and the interface between Cu and Mo remains sharp and planar in all specimens. Annealing of a Cu 0.6 nm/Mo 20 nm multilayer produced three-dimensional arrays of Cu nanoparticles lying along the previous interface. These Cu nanoparticles have an average particle size of roughly 2 nm with a bcc structure. Temperature-dependent resistivity measurements in as-deposited and annealed samples are reported. These data indicate that carrier scattering changes markedly as the system evolves from one that consists predominantly of planar interfaces to one dominated by spherical scattering centers