The effect of NH3 on TiO2 film deposition using tetrakis(diethylamino)titanium (TDEAT) and O2 as source gases in a low pressure chemical vapor deposition reactor was studied at low temperatures ranging from 100 to 250 °C. TiO2 film is traditionally deposited at temperature above 300 °C using oxygen-based Ti precursors, such as titanium tetraisopropoxide. In this study, the authors demonstrate that a combination of both reactive precursors, i.e., TDEAT and NH3, is an effective technique for TiO2 film deposition at lower temperatures, albeit with some nitrogen incorporation. It was found that films can be formed at temperatures as low as 100 °C when NH3 is used. At higher temperatures, the growth rate of TiO2 films deposited using NH3 is higher than that of films deposited without NH3 by up to one order of magnitude. X-ray photoelectron spectroscopy data show that NH3 enhances the formation of TiNO and TiN, and x-ray diffraction analysis shows that all as-deposited films have amorphous structure. Both x-ray photoelectron spectroscopy and secondary ion mass spectroscopy depth profiles show that nitrogen, carbon, and oxygen are uniformly distributed throughout the f- - ilm. The mechanism of enhancement of growth rate using NH3 is also discussed.