A process and apparatus for the low pressure, cold wall, chemical vapor deposition of refractory metals, such as tungsten on a silicon wafer. The silicon wafer is introduced into a loading lock wherein the pressure is reduced to subatmospheric pressure. The silicon wafer is transferred to a deposition chamber where it is heated to an elevated temperature. A refractory metal carbonyl vapor is introduced into the deposition chamber and dissociates to deposit a refractory metal on the silicon wafer. The wafer is transferred to an unloading lock where it is allowed to cool and is then removed.