Effect of N2/Ar flow ratio on the structural and electrical properties of SrHfON thin films prepared by magnetron sputtering

SrHfON thin films were prepared by radio frequency (RF) magnetron reactive co-sputtering under various N-2/Ar flow ratio in the range from 0.20 to 0.50. The effect of N-2/Ar flow ratio on the deposition rate, composition, structure and electrical properties of the sputtered SrHfON films has been investigated using X-ray spectroscopy (XPS), grazing incidence X-ray diffraction (GI-XRD), leakage current density-voltage (J-V) and capacitance voltage (C-V) measurements. The results show that the properties of the SrHfON films were greatly affected by the N-2/Ar flow ratio. The deposition rate of the SrHfON films was found to decrease with the increasing N-2/Ar flow ratio. The SrHfON films exhibited local crystallization when the N-2/Ar flow ratio is low (<033) while the SrHfON films were amorphous when the N-2/Ar flow ratio is high (>0.33). The average leakage current density of the SrHfON films decreases initially and then increases with the increasing N-2/Ar flow ratio. Contrarily, the dielectric constant (k) of the SrHfON films increases firstly and then decrease with the increasing N-2/Ar flow ratio. Moreover, both the flat-band voltage shift and fixed positive charge densities were decreased initially and then increased with the increase of N-2/Ar flow ratio. (C) 2014 Elsevier Ltd. All rights reserved.