Methods and apparatuses are described that provide tungsten deposition with low roughness. In some embodiments, the methods involve co-flowing nitrogen with hydrogen during an atomic layer deposition process of depositing tungsten that uses hydrogen as a reducing agent. In some embodiments, the methods involve depositing a cap layer, such as tungsten oxide or amorphous tungsten layer, on a sidewall surface of a 3D NAND structure. The disclosed embodiments have a wide variety of applications including depositing tungsten into 3D NAND structures.