We have studied the influence of varying the oxygen flow rate (FO2) on the deposition rate and composition of sub-stoichiometric titanium oxide films deposited by rf-sputtering. Rutherford backscattering is used for the composition and perfilometry for the growth rate. An abrupt reduction of the growth rate is observed for FO2 larger than 0.050 sccm. This effect coincides with the formation of TiO2 films with x=1.78, which increases up to x=1.92 for FO2=6 sccm. For FO2 ~ 0.054 sccm, Ti films with about 24 at.% O content are obtained. The oxide films exhibit a mixture of the rutile and anatase TiO2 structures (as determined by X-ray diffraction), whose relative contribution changes little with FO2. A small but noticeable decrease of the crystallite size with increasing FO2 can be deduced from the X-ray diffraction patterns.
