Synthesis, Nano-Structure and Electrical Properties of TiOz by Annealing of TiThin Films

Ti film s 01 246.2 nm were deposited , using resistive heat meth od and post-annealed at 373 . 473. and 573 K with flow ofoxygen. The nano-stru ctur es of the film s were obtained using X-ray di ffract ion (XRD) and atomic force microscopy(AFM) . The resul ts showed an initial redu ction of the gra in size at 373 K annea ling temp eratu re and increase of thegrain size at high er temperatures. The cause of this was due to the reacti on of oxygen with Ti atoms which breaks up theTi gr ains and hence smaller featu res form. The increase of annealing tem perature to 473 K and 573 K enh ances the activation processes. hence diffu sion effec t and result s in larger gra ins . The resisti vity of the film s increased with annealingtemperature, which is due to competition between incr eased diffusion rate and the increased reaction rate of oxygen with Ti atoms. The latt er increases the resisti vity of the thin film while the form er decreases its resi stivity. The results showedthat. conductiv ity, carrier conce ntration and the mobility decrease with increasing the annealing temperatu re. cons istentwi th the formation of higher level of semiconductive Ti0 2 . The Arr henius plots of (J and RH resulted in act ivation ener giesof 0.4 2 and 0.4 eV. respectively.