Impact of nitrogen reactive gas and substrate temperature on the optical, electrical and structural properties of sputtered TiN thin films

• Published in: Journal of materials science. Materials in electronics 2020-11, Vol.31 (22), p.20009-20021
• Main Authors: Mustapha, N., Fekkai, Z.
• Format: Article
• Language: English
• Subjects: Absorption spectra; Atomic force microscopy; Characterization and Evaluation of Materials; Chemistry and Materials Science; Crystal structure; Crystallinity; Crystallites; Direct current; Electrical resistivity; Energy gap; Flow velocity; Glass substrates; Magnetron sputtering; Materials Science; Mathematical analysis; Morphology; Nitrogen; Optical and Electronic Materials; Optical properties; Protective coatings; Reflectance; Refractivity; Thickness; Thin films; Titanium nitride
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-020-04523-z

This work was aimed to study the influence of nitrogen reactive gas and substrate temperature, on the crystalline structure, morphology, sheet resistance and optical properties of titanium nitride thin films. The samples were deposited on glass substrates by the direct current reactive magnetron sputtering method and were controlled to have thicknesses of 150 nanometer (nm). The crystal structures of the samples were checked using the X-ray diffraction technique. The average crystallite size was calculated by using the Scherrer equation. Atomic Force Microscopy was performed on all samples to investigate any change in the crystallite sizes, morphology and also in the roughness of the film’s surface. With the variation in substrate temperature, the optical properties (refractive index, optical band gap and extinction coefficient) of films also changed. The experimental reflectance and absorption spectra of the samples have been characterized by spectrophotometer measurements. Optical band-gap values decrease from 4.01 eV at 300 °C to 3.59 eV at 500 °C. Optical refractive index ( n ) and extinction coefficient ( k ) are strongly dependent on the flow rate of nitrogen and substrate temperature. Furthermore, the sheet resistance of the TiN samples are dependent on the investigated deposition parameters. The high reflectance, good morphology, improved crystallinity and low sheet resistance maintained by the films, made them very favorable to be used in both optical and electronic applications, and also as protective and decorative coatings.