The process simplification value of integrated polycide (in-situ doped silicon film integrated with tungsten silicide) is reviewed. The characterization of tungsten and silicon composition in the interface region and its dependence on phosphorus content in the silicon is developed. High concentrations of phosphorus are shown to be a controlling factor driving the composition to be tungsten rich; variations in silane or disilane chemistry and silicon deposition temperature spanning from amorphous as-deposited to polycrystalline are minor factors. With the objective of increasing the interfacial Si:W ratio to improve film quality, we report the extension of Si rich films into the mid E20 atoms/c.c. phosphorus doping range.