Electrical and optical properties of titanium nitride coatings prepared by atmospheric pressure chemical vapor deposition

In order to examine the possibility for TiN coatings to be low-E, TiN coatings were deposited on the glass substrates by atmospheric pressure chemical vapor deposition using titanium tetrachloride (TiCl4) and ammonia (NH3) as precursors. X-ray diffraction, sheet resistance measurement, optical transmittance spectroscopy and infrared reflectance spectroscopy were carried out to determine the relationships between the preparation parameters and the microstructure, electrical and optical properties of the coatings. The results showed that the concentration of crystals increased with increasing the substrate temperature and the flow of TiCl4, resulting in a decrease of the electrical resistivity. The optical transmittance of TiN thin films was strongly dependent on the gas flow and the substrate temperature. Under optimum conditions, continuous polycrystalline TiN coatings with FCC structure were obtained with an electrical conductivity around 34.5 Ω/□, an optical transmittance around 50% in the visible range, and an infrared reflectance higher than 50% above 3000 nm. This indicates that TiN coated glasses may be possible candidates for high IR reflectance windows.