Pulsed DC- Plasma Assisted Chemical Vapor Deposition of α-rich Nanostructured Tantalum Film: Synthesis and Characterization

This paper is an attempt to synthesize nanostructured tantalum films on medical grade AISI 316L stainless steel (SS) using pulsed DC plasma assisted chemical vapor deposition (PACVD). The impact of duty cycle (17-33%) and total pressure (3-10 torr) were studied using field emission scanning electron microscopy (FESEM), grazing incidence x-ray diffraction (GIXRD), nuclear reaction analysis (NRA), proton induced x-ray emission (PIXE) and Rockwell indentation methods. The optimized deposition conditions for making the best film characteristics in terms of deposition rate, purity and maximum α-phase was recognized. Also, the results showed that using a near stoichiometric TaN interlayer in this technique improves the film adhesion strength and considerably increases Ta film purity. The NRA analysis results indicated that the pulsed DC-PACVD is capable of producing Ta films with negligible amount of residual hydrogen which makes films needless to post bake treatment.