Influence of Nitrogen Vacancy Concentration on Mechanical and Electrical Properties of Rocksalt Zirconium Nitride Films

To study the influence of the nitrogen vacancy （VN） on mechanical and electrical properties of zirconium nitride deeply, ZrNx films with different VN 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 ZrNx films exhibited rocksalt single-phase structure within a VN concentration ranging from 26 to 5%. The preferred orientation, thickness, grain size and residual stress of the ZrNx films kept constant at different VN concentrations. Both the nanohardness and elastic modulus first increased and then decreased with the decrease in VN concentration, reaching the peaks around 16%. And the electric conductivity of the ZrNx films showed a similar tendency with nanohardness. The underlying atomic-scale mechanisms of VN 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.

Abstract To study the influence of the nitrogen vacancy （VN） on mechanical and electrical properties of zirconium nitride deeply, ZrNx films with different VN 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 ZrNx films exhibited rocksalt single-phase structure within a VN concentration ranging from 26 to 5%. The preferred orientation, thickness, grain size and residual stress of the ZrNx films kept constant at different VN concentrations. Both the nanohardness and elastic modulus first increased and then decreased with the decrease in VN concentration, reaching the peaks around 16%. And the electric conductivity of the ZrNx films showed a similar tendency with nanohardness. The underlying atomic-scale mechanisms of VN 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.