at a pressure between about 1 u00d7 10 6 and 1 u00d7 10 4 and annealing the treated layer at the deposition temperature application_number US 17834298 A description the specific method of the present invention to achieve a smoother surface on the sample is defined as follows a substrate onto which a refractory metal such as metallic tungsten is to be deposited is introduced via a load lock as depicted in fig7 into the deposition chamber the material is typically silicon silicon dioxide or silicon nitride but may be any material provided it can withstand heating to 500 u00b0 c and does not react rapidly with the refractory metal chosen at that temperature the reactor is typically a stainless steel cold wall ultrahigh vacuum system with a base pressure better than 1 u00d7 10 6 torr preferably better than 1 u00d7 10 7 torr most preferably 1 u00d7 10 9 the low pressure of the system is desirable in order that the oxygen partial pressure can be accurately and reproducibly controlled the substrate is heated to the deposition temperature which is typically 500 u00b0 c but may vary according to the substrate and the specific deposition method the precursor gas for cvd deposition e g tungsten hexacarbonyl for tungsten deposition is admitted to the reactor under flow conditions to a pressure of approximately 3 u00d7 10 3 torr while this process is described as using tungsten hexacarbonyl any precursor gas suitable for the deposition of pure tungsten or any other suitable pure refractory metal with the requisite metastable phase as described above may be used by way of illustration specifically for tungsten cvd using tungsten hexafluoride as a precursor gas may be selected.