Characterisation of TiO2 deposited by photo-induced chemical vapour deposition

We report the deposition of thin TiO2 films on crystalline Si and quartz by photo-induced chemical vapour deposition (CVD) using UV excimer lamps employing a dielectric barrier discharge in krypton chloride (KrCl∗) to provide intense narrow band radiation at λ=222 nm. The precursor used was titanium isopropoxide (TTIP). Films from around 20–510 nm in thickness with refractive indices from 2.20 to 2.54 were grown at temperatures between 50 and 350 °C. The higher refractive index values compare favourably with the value of 2.58 recorded for the bulk material. The measured deposition rate was around 50 nm/min at 350 °C. Fourier transform infrared spectroscopy (FTIR) revealed the presence of TiO2 through the observation of a Ti–O absorption peak and the absence of OH in films deposited at 250–350 °C indicated relatively good quality films. The phase of films deposited at 200–350 °C was anatase as determined by X-ray diffraction.