Structural characterization of DC magnetron-sputtered TiO_2 thin films using XRD and Raman scattering studies

摘要

Titanium dioxide films have been deposited using DC magnetron sputtering technique onto well-cleaned p-silicon substrates at an oxygen partial pressure of 7 * 10~(-5) mbar and at a sputtering pressure (Ar + O_2) of 1 * 10~(-3) mbar. The deposited films were calcinated at 673 and 773 K. The composition of the films as analyzed using Auger electron spectroscopy reveals the stoichiometry with an O and Ti ratio 2.08. The influence of post-deposition annealing at 673 and 773 K on the structural properties of the titanium dioxide thin films have been studied using XRD and Raman scattering. The structure of the films deposited at the ambient was found to be amorphous and the films annealed at temperature 673 K and above were crystalline with anatase structure. The lattice constants, grain size, microstrain and the dislocation density of the film are calculated and correlated with annealing temperature. The Raman scattering study was performed on the as-deposited and annealed samples and the existence of Raman active modes A_(1g), B_(1g) and E_g corresponding to the Raman shifts are studied and reported. The improvement of crystallinity of the TiO_2 films was also studied using Raman scattering studies.