The properties of rf‐magnetron‐sputtered NbN have been investigated for substrate temperatures from 200°C to 750°C as a function of the partial pressure of methane introduced into the Ar–N2 sputtering gas mixture. The best films were prepared at elevated substrate temperatures with approximately 2% methane added to the sputter gas. These films also had resistivities approximately 70 μΩ cm. At lower substrate temperature, T∼200°C, the best attained Tc was approximately 13.3 K with a resistivity of 140 μΩ cm. The crystal structure of these materials was investigated using x‐ray diffraction and Read x‐ray photographs. Those films prepared with no added methane were found to be two‐phase δ and ϵ NbN. The addition of a small amount of methane produced single δ phase NbN with a predominant (200) preferrential orientation. The δ phase lattice parameter was determined to vary approximately from 4.39 Å to 4.45 Å as the amount of methane was increased. The effect of hydrogen doping on NbN was to produce multiphase NbN with the ϵ, δ phases and some evidence of the β phase. These material properties are of importance for the design and fabrication of NbN electrode Josephson tunnel junctions.