Methods for forming a liner layer are provided herein. In some embodiments, a method of forming a liner layer on a substrate disposed in a process chamber, the substrate having an opening formed in a first surface of the substrate, the opening having a sidewall and a bottom surface, the method includes exposing the substrate to a cobalt precursor gas and to a ruthenium precursor gas to form a cobalt-ruthenium liner layer on the first surface of the substrate and on the sidewall and bottom surface of the opening.