A multiple step chemical vapor deposition process for depositing a tungsten layer on a substrate (16). A first step of the depostion process includes a nucleation step in which WF6 and SiH4 are introduced into a deposition chamber (step 200). Next, the flow of WF6 and SiH4 are stopped and diborane is introduced into the chamber (12) for between 5-25 seconds (step 210). Finally, during a bulk deposition step, the WF6 is reintroduced into the chamber along with H2 and B2H6 flows to deposit a tungsten layer on the substrate (step 220). In a preferred embodiment, the bulk deposition step also introduces nitrogen into the process gas.
