Deposition and characterization of NiAl and Ni-Al-N thin films from a NiAl compound target

NiAl and Ni-Al-N thin films have been deposited from a dense and homogeneous NiAl compound target onto various substrates, including stainless steel, glass, and Si100 wafer, by using RF magnetron sputtering. The films have been characterized using X-ray diffraction, X-ray photoelectron spectroscopy, Auger electron spectroscopy, scanning electron microscopy, and scanning transmission electron microscopy. Both the NiAl and Ni-Al-N thin films exhibited the near equiatomic NiAl phase. The Ni-Al-N thin films showed an increasing nitrogen content with increasing the amount of N₂ in the sputtering atmosphere during deposition. XPS spectra confirmed the possible formation of aluminum nitride in the Ni-Al-N films. The texture, composition, and microstructure of the NiAl films change with the discharge power used. The NiAl thin films deposited using 500 W RF power exhibited the microstructure of a 0.5-0.7-μm amorphous layer adjacent to the substrate and a dense and columnar zone T crystalline microstructure which had a preferred orientation [110]. The Ni-Al-N films showed a homogeneous microstructure of very fine (nano scale) NiAl (110) grains distributed into an amorphous matrix. The results confirm the feasibility of producing high-quality NiAl and Ni-Al-N thin films from a NiAl compound PVD target.