The influence of annealing on the optical properties and microstructure recrystallization of the TiO2 layers produced by means of the E-BEAM technique

Abstract

Titanium dioxide films, about 200 nm in thickness, were deposited using the e-BEAM technique at room temperature and at 227◦C (500K) and then annealed in UHV conditions (as well as in the presence of oxygen (at 850◦C). The fabricated dielectric films were examined using X-ray powder diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy, scanning electron microscopy, transmission electron microscopy, and spectroscopic ellipsometry. The applied experimental techniques allowed us to characterize the phase composition and the phase transformation of the fabricated TiO2 coatings. The films produced at room temperature are amorphous but after annealing consist of anatase crystallites. The layers fabricated at 227◦C contain both anatase and rutile phases. In this case the anatase crystallites are accumulated near the substrate interface whilst the rutile crystallites were formed closer to the surface of the TiO2 film. It should be emphasized that these two phases of TiO2 are distinctly separated from each other.