Characterisation of TiO 2 deposited by photo-induced chemical vapour deposition

Abstract

We report the deposition of thin TiO 2 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 TiO 2 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.