Deposition of thin titania films by dielectric barrier discharge at atmospheric pressure

A homogeneous atmospheric pressure dielectric barrier discharge is studied. It is in argon with small admixtures of titanium tetrachloride vapour and oxygen for the deposition of thin titania films on glass substrates. A special electrode configuration was applied in order to deposit the titania film uniformly. The sustaining voltage (6 kV to 12 kV), current density (about 3 mA/cm(2)) and total optical emission spectroscopy were monitored to characterize the discharge in the gap of 2 mm. Typical deposition rates ranged from approximately 30 nm/min to 120 nm/min. The film morphology was investigated by using scanning electron microscopy (SEM) and the composition was determined with an energy dispersive x-ray spectroscopy (EDS) analysis tool attached to the SEM. The crystal structure and phase composition of the films were studied by x-ray diffraction (XRD). Several parameters such as the discharge power, the ratio of carrier gas to the precursor gas, the deposition time on the crystallization behavior, the deposition rate and the surface morphology of the titania film were extensively studied.