Methods for plasma treatment of films to remove impurities are disclosed herein. Methods for removing impurities can include positioning a substrate with a barrier layer in a processing chamber, the barrier layer comprising a barrier metal and one or more impurities, maintaining the substrate at a bias, creating a plasma comprising a treatment gas, the treatment gas comprising an inert gas, delivering the treatment gas to the substrate to reduce the ratio of one or more impurities in the barrier layer, and reacting a deposition gas comprising a metal halide and hydrogen-containing gas to deposit a bulk metal layer on the barrier layer. The methods can further include the use of diborane to create selective nucleation in features over surface regions of the substrate.