A method for forming a ruthenium metal layer includes providing a patterned substrate in a process chamber of a deposition system, where the patterned substrate contains one or more vias or trenches, or combinations thereof, depositing a first ruthenium metal layer on the substrate in an atomic layer deposition process, and depositing a second ruthenium metal layer on the first ruthenium metal layer in a thermal chemical vapor deposition process. The deposited ruthenium metal layer can be used as a diffusion barrier layer, a seed layer for electroplating, or both.