Abstract:

To study the influence of the nitrogen vacancy (V_N) on mechanical and electrical properties of zirconium nitride deeply, ZrN_x films with different V_N concentrations were synthesized on the Si (111) substrates by enhanced magnetic filtering arc ion plating. The morphologies, microstructures, residual stresses, compositions, chemical states, mechanical and electrical properties of the as-deposited films were characterized by field-emission scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectrometry, Nanoindenter and Hall effect measurements. The results showed that ZrN_x films exhibited rocksalt single-phase structure within a V_N concentration ranging from 26 to 5%. The preferred orientation, thickness, grain size and residual stress of the ZrN _x films kept constant at different V_N concentrations. Both the nanohardness and elastic modulus first increased and then decreased with the decrease in V_N concentration, reaching the peaks around 16%. And the electric conductivity of the ZrN _x films showed a similar tendency with nanohardness. The underlying atomic-scale mechanisms of V_N concentration-dependent hardness and electric conductivity enhancements were discussed and attributed to the different electronic band structures, rather than conventional meso-scale factors, such as preferred orientation, grain size and residual stress.

Key words: ZrNx films, Nitrogen vacancy, Hardness, Electrical properties, Band structure