Temperature dependent structural, optical and hydrophobic properties of sputtered deposited HfO2 films

Hafnium oxide being high-k dielectric has been successfully utilized in electronic and optical applications. Being thermodynamically stable and having good mechanical strength, it can be used as a protective coating for outdoor HV insulators which are suffering from surface flashover problem due to contamination. In this paper, we are investigating the effect of substrate temperature on structural, optical and hydrophobic properties of hafnium oxide coating deposited over glass insulators by DC magnetron sputtering. X-ray diffraction is applied to determine the crystalline phase and crystallite size of the film. The morphology of the samples is examined using atomic force microscopy. The optical properties are studied using UV-vis-NIR spectrophotometer. The wettability of the film is investigated using contact angle meter. The thickness is measured using surface profilometer and verified through optical data. The relationship between substrate temperature with grain size, roughness, refractive index, and hydrophobicity is manifested. The maximum contact angle for HfO2 film was found to be 106° at 400°C