Pd–Ag alloy films prepared by metallorganic chemical vapor deposition process

Abstract

Palladium–silver alloy films were prepared by a hot-wall metallorganic chemical vapor deposition process, using a mixed inlet stream of two precursor vapors, palladium acetate and silver acetate. The Pd–Ag alloy film was obtained at a deposition temperature below 500°C and was composed of 20–40 nm grains as determined from the X-ray diffraction data. On top of the dense Pd–Ag film, there was found sub-micrometre aggregates of nano-sized primary particles, resulting from a gas-phase reaction of precursor vapors and subsequent coagulation and partial sintering of nano-sized primary particles. The Ag content of the film was found to be decreasing from the film surface into the film itself. Separate placement of the two precursors gave a stronger control on the film composition, than adjusting the mixing ratio of the two precursors for the mixed precursor practice. The deposition flux and Pd content of the film decreased with increasing distance from the reactor entrance.