Microstructural and optical properties of Sputter deposited Hafnium oxynitride films on glass substrate

The main purpose of this work was to prepare hafnium oxynitrides (HfO_xN_y) thin films as a protective coating for outdoor high voltage insulators. Hafnium oxynitride thin films had been investigated because of their remarkable properties in the domains of protective applications. HfO_xN_y thin films were deposited by DC reactive magnetron sputtering from a pure Hf target onto glass and quartz substrates at room temperature. The depositions were carried out under an oxygen-nitrogen-argon atmosphere by varying the flow rate of the reactive gas oxygen keeping the flow rate of nitrogen and oxygen constant. The variation of the flow rate of the reactive gas oxygen was studied on the structural optical and hydrophobic properties of the films. Glancing incidence X-ray diffraction (GIXRD) was used to study the structural changes of as-deposited films; crystalline hafnium oxynitride phase were formed as oxygen partial pressure is varied. Also the grain size decreases as partial pressure of oxygen increases. Surface roughness as measured from atomic force microscopy (AFM) image also decreases as oxygen flow rate was changed from 10% to 40%. Optical property of the films was observed through UV spectrophotometer. The band gap, refractive index and thickness were calculated using optical data. The thickness was also measured using surface profilometer. The coating so developed is hydrophobic but its hydrophobicity decreases as oxygen content increases.