Electroplated Ru and RuCo films as a copper diffusion barrier

•Cu/RuxCo1−x stacking was deposited on textured NiSiy/Si by electroplating.•For the Ru barrier, the copper atoms diffuse into silicon at a temperature of 400 °C.•The diffusion of Cu atoms was effectively suppressed in the RuxCo1−x barrier.•The diffusion of Cu is accelerated as the annealing temperature increases.