Structure of reactively sputtered nickel nitride films

Thin nickel nitride films were prepared by reactive sputtering of nickel in an ArN2 gas mixture. The structure of these films was investigated with X-ray and electron diffraction and was found to depend on the partial N2 pressure during the sputtering process. All nickel nitrides reported earlier, except Ni3N2, were observed in the sputtered films. At high partial N2 pressures a body-centred tetragonal phase was observed. Up to now, this phase has not been explicity reported as a nickel nitride. On the basis of our results we believe that the phase is another nickel nitride, namely Ni2N.