30 32 36 and 38 as well as mass flow controllers mfcs 34 and 40 are used to control the u201c on off u201d and flow rate of h 2 and nh 3 fig2 illustrates shows an example operating sequence the h 2 can be turned on and off as indicated by sequence 60 alternating the h 2 causes the tungsten source that it carries to alternate the nh 3 can also be turned on and off as indicated by sequence number 62 keeping the nh 3 on while h 2 alternates as shown in region 70 allows the incoming tungsten source time to fully react with the nh 3 for full nitridation of the resulting film therefore the as deposited films have a high density the alternating source will also produce a smaller grain size than that produced without alternating the source due to the grain growth being on and off in accordance with the h 2 flow if the nh 3 is turned off while allowing the h 2 to either remain on or alternate will produce a layer of w by alternately turning the nh 3 on and off as shown in region 76 it is possible to produce films of wn w in alternating layers these alternating layers will produce even finer grains or possibly amorphous films as well as providing films with low resistivity values as shown in fig2 sequences of keeping nh 3 steady while alternating h 2 region 70 can be combined with sequences that alternate h 2 while keeping nh 3 steady region 76 to tailor the film or film stack and its corresponding.