Interrelationships between process parameters, structure, and properties of CVD tungsten and tungsten–rhenium alloys

Abstract

The development of CVD techniques for fabricating free-standing tungsten and tungsten–rhenium alloy structures is reviewed. Relationships between plating parameters, kinetics, morphology, microstructure, and properties of thick polycrystalline deposits are discussed. It is emphasized that porosity may be grown into the grain boundaries when the depostition rate is controlled by gas phase diffusion, and that fully dense deposits are generally obtained when the rate is limited by a surface process. The origin and control of many of the microstructural features peculiar to CVD are also discussed.