Cobalt deposition selectivity on copper and dielectrics

A process for forming cobalt on a substrate, comprising: volatilizing a cobalt precursor of the disclosure, to form, a precursor vapor: and contacting the precursor vapor with the substrate under vapor deposition conditions effective for depositing cobalt on the substrate from the precursor vapor, wherein the vapor deposition conditions include temperature not exceeding 200° C., wherein: the substrate includes copper surface and dielectric material, e.g., ultra-low dielectric material. Such cobalt deposition process can be used to manufacture product articles in which the deposited cobalt forms a capping layer, encapsulating layer, electrode, diffusion layer, or seed for electroplating of metal thereon, e.g., a semiconductor device, flat-panel, display, or solar panel. A cleaning composition containing base and oxidizing agent components may be employed to clean the copper prior to deposition of cobalt thereon, to achieve substantially reduced defects in the deposited cobalt.