Methods for controlling crystal size in bulk tungsten layers are disclosed herein. Methods for depositing a bulk tungsten metal layer can include positioning a substrate with a barrier layer in a processing chamber, forming a tungsten nucleation layer, post-treating the nucleation layer with one or more treatment gas cycles including an activating gas and a purging gas, heating the substrate to a deposition temperature, and depositing a bulk tungsten layer with alternating nitrogen flow on the nucleation layer. The post-treatment cycling can be applied optionally to the bulk metal deposition with alternating nitrogen flow.