Influence of N2 flow ratio on the properties of hafnium nitride thin films prepared by DC magnetron sputtering

Hafnium nitride (Hf-N) thin films were deposited on fused silica at different N2 flow ratio (N2/N2 + Ar) using a reactive DC magnetron sputtering system. A gradual evolution in the composition of the films from Hf3N2, HfN, to higher nitrides was found through X-ray diffraction (XRD). Films of Hf3N2 and HfN show positive temperature coefficients of resistivity, while higher nitride has a negative one. Highly oriented growth of (0 0 1) Hf3N2 and NaCl-structure (1 0 0) HfN films were fabricated on fused silica substrate at relatively lower temperature of 300 °C. The electrical resistivity values of both as-deposited and post-deposition annealed films were measured by a four-point probe method. The obtained minimum resistivity of as-deposited film is 20 μΩ cm, and this result shows potential application of HfN films as electrode materials in electronic devices.