Microstructural and Optical properties of Sputter deposited Hafnium oxynitride films on glass substrate V. Dave 1,2 , P. Dubey 2 , H.O. Gupta 1 , R. Chandra 2 1 Department of Electrical Engineering, Indian Institute of Technology Roorkee-247667, India 2 Institute Instrumentation Centre, Indian Institute of Technology Roorkee-247667, India Abstract-The main purpose of this work was to prepare hafnium oxynitrides (HfO x N 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 x N 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. Keywords: Contamination, Sputtering, Hydrophobicity I. Introduction Nitrides of High K material such as HfO 2 , ZrO 2 have shown excellent properties in the synthesis of gate dielectrics. Although high K oxides have high heat formation, the defect densities in these metal oxides are very high. This defect increases the leakage current. To overcome these leakage current, nitrogen atoms is added [1]. Hafnium oxynitrides has been deposited by many techniques like chemical vapour deposition [2], physical vapour deposition [3] etc. The enhanced properties of hafnium oxynitride can be used in the areas where hafnium oxide has been successfully utilized. So far they have mostly utilized for gate dielectric purpose. They can be used as protective coating for many applications. Electrical insulating system is one such area. Outdoor high voltage electrical insulators are facing a problem of contamination. These contaminations degrade the insulator surface and hence are the cause for the electrical flashover. Various methods have been suggested to overcome this problem. To develop hydrophobic dielectric coating over the surface of the insulator is one such method [4]. In this paper, we are investigating the structural and optical characteristic of hafnium oxynitrides films over glass substrate. II. Experiment Hafnium oxynitride thin films were deposited on glass and quartz substrates by DC magnetron sputtering in a 12 inch diameter chamber (Excel Instruments, India) using 99.99% pure hafnium target (2 in. diameter and 5-mm thick) .The substrates were cleaned in ultrasonic baths of acetone. Further the substrates were dried under nitrogen gas and mounted onto the substrate holder having a distance 5cm from the target. The chamber was evacuated by a turbo pump. The turbo pump is backed by a rotary pump for creating rough vacuum. The base pressure was kept below 3x10 -6 Torr. Thereafter high purity (99.9%) oxygen, nitrogen along with inert gas (Ar) was passed into the chamber. The flow of nitrogen and argon was kept constant (20 sccm) while the oxygen gas partial pressure was varied from 10% to 40%. The ratio of the gas mixture was controlled using mass flow controller while flow was measured using capacitance manometers. The gas pressure was kept at 20 mTorr for all depositions. The gas pressure was kept constant for each deposition since sputtering current is highly sensitive to sputtering gas pressure. The sputtering was carried for a period of one hour at room temperature. The power was kept 50W.All parameters were kept constant during each deposition process except oxygen gas flow. 978-1-4673-6150-7/13/$31.00 ©2013 IEEE 1031