Sputtering-Pressure Dependent Optical and Microstructural Properties Variations in DC Reactive Magnetron Sputtered Titanium Nitride Thin Films

Abstract

Titanium nitride thin films were prepared using DC reactive magnetron sputtering process in a 99.998% reactive nitrogen atmosphere. The sputtering pressure was varied to study its influence on the as-deposited films, using low (0.80 Pa), intermediate (3.40-5.33 Pa) and high (11.33 Pa) sputtering pressures. The deposited films possessed colour that ranged from dark blue, characteristic of oxygen-rich titanium nitride films, to reflective golden yellow, reminiscent of stoichiometric TiN_x films. Studies on the optical and microstructural properties were carried out using UV-visible spectrophotometry, scanning electron microscopy (SEM) and X-ray diffractometry. Characterization results showed variation in the optical and structural properties of the film depending on the deposition sputtering pressure with relatively higher enhancement in the optical transmittance of up to 97.52% in the visible region for films deposited under high and intermediate sputtering pressure conditions. The deposition rate of the films was found to decrease with sputtering pressure. In the same vein, the optical transmittance of the films reduced from 97.52 to 10.05% and the transmission band shifted towards higher wavelength with the decrease of the sputtering pressure.