Chemical composition, crystallographic structure and impedance spectroscopy of titanium oxynitride TiNxOy thin films

Abstract

Titanium oxynitride TiNxOy thin films have been deposited by DC-pulsed magnetron sputtering from Ti target in the Ar + N2 + O2 reactive atmosphere controlled by plasma emission spectroscopy. Correlation between chemical composition and crystallographic structure of thin films has been determined and presented in the form of the pseudo-equilibrium ternary phase diagram. The atomic N/Ti and O/Ti ratios have been derived from Rutherford backscattering (RBS) measurements. X-ray diffraction at grazing incidence has revealed formation of defective TiN-TiO solid solutions. The surface roughness estimated from atomic force microscopy (AFM) surface images decreases with increasing oxygen content in the films, in accordance with the progressive sample amorphisation. Impedance spectroscopy measurements indicate that the electrical conductivity changes its character from metallic to semiconducting with increasing oxygen content in TiNxOy thin films