Systems and methods for sputtering a layer of refractory metal layer onto a barrier layer disposed on a substrate are disclosed herein. In one or more embodiments, a method of sputter depositing a tungsten structure in an integrated circuit includes: moving a substrate into a plasma processing chamber and onto a substrate support in opposition to a sputter target assembly comprising a tungsten target having no more than ten parts per million of carbon and no more than ten parts per million of oxygen present as impurities; flowing krypton into the plasma processing chamber; and exciting the krypton into a plasma to deposit, by sputtering, a tungsten film layer on a material layer of a substrate supported by the substrate support. In some embodiments, the target assembly further includes a titanium backing plate and an aluminum bonding layer disposed between the titanium backing plate and the tungsten target.