Formation of composite tungsten films

Abstract

Embodiments of the invention provide methods for depositing tungsten materials. In one embodiment, a method for forming a composite tungsten film is provided which includes positioning a substrate within a process chamber, forming a tungsten nucleation layer on the substrate by subsequently exposing the substrate to a tungsten precursor and a reducing gas containing hydrogen during a cyclic deposition process, and forming a tungsten bulk layer during a plasma-enhanced chemical vapor deposition (PE-CVD) process. The PE-CVD process includes exposing the substrate to a deposition gas containing the tungsten precursor while depositing the tungsten bulk layer over the tungsten nucleation layer. In some example, the tungsten nucleation layer has a thickness of less than about 100 Å, such as about 15 Å. In other examples, a carrier gas containing hydrogen is constantly flowed into the process chamber during the cyclic deposition process.