Nano Structure and Electrical Properties of Annealed Ti Thin Films

Ti films of 66.8 nm were deposited, using resistive heat method and post-annealed at different temperatures with flow of oxygen. The nano-structures of the films were obtained using X-ray diffraction (XRD) and atomic force microscopy (AFM). The results showed an initial reduction of the grain size at 373 K annealing temperature and increase of the grain size at higher temperatures. The cause of this was due to the reaction of oxygen with Ti atoms which breaks up the Ti grains and hence needle–like features form. The increase of annealing temperature to 473 and 573 K enhances the activation processes, hence diffusion effect and results in larger grains. The resistivity of the film increased with annealing temperature, which is due to competition between increased diffusion rate and the increased reaction rate of oxygen with Ti atoms. The latter increases the resistivity of the thin film while the former decreases its the resistivity.