Formation process of Ni–N films by reactive sputtering at different substrate temperatures

Abstract

Ni–N thin films are prepared by reactive sputtering in an rf diode sputtering system. Deposition parameters, such as nitrogen flow ratio, substrate temperature and substrate holder potential were changed and their effects were investigated. When the substrate was heated at 220°C, Ni and Ni 3N phases were observed by XRD. In the case of substrate temperature being room temperature (RT), Ni 2N phase also appeared and characteristic nitrogen incorporation into Ni lattice was seen. In addition, when the substrate holder was set to the float potential, nitrogen content of the film which is thought to be lower than the case of ground potential, caused stronger resputtering effect. Because it was observed that the formation phase and nitrogen content of the film depend on the substrate temperature, the nitrogenizing reaction on the deposit surface was considered to rule the film formation. This was also supported by the results on the target surface analysis after sputtering and plasma emission spectroscopy measurements.