Thermal annealing of amorphous Ti–Si–O thin films

Ti–Si–O thin films were deposited using an aerosol chemical vapor deposition process at atmospheric pressure. The film structure and microstructure were analyzed using several techniques before and after thermal annealing. Diffraction results indicate that the films remain x-ray amorphous after annealing, whereas Fourier transform infrared spectroscopy gives evidence of a phase segregation between amorphous SiO₂ and well-crystallized anatase TiO₂. Crystallization of anatase TiO₂ is also clearly shown in the Raman spectra. Transmission electron microscopy analysis indicates that anatase TiO₂ nanograins are embedded in a SiO₂ matrix in an alternated SiO₂/TiO₂ multilayer structure.