We investigated characteristic of the In2O3 films deposited by various atomic layer deposition (ALD) conditions such as growth temperature and doses of ethylcyclopentadienyl indium (InEtCp) precursor and H2O/O3 oxidant gases. A self-limited ALD window was observed in the In2O3 film deposition when an InEtCp and H2O/O3 doses were supplied over 27.6 μmol and 0.09/2,94 mmol, respectively, regardless of the growth temperature. The ratio of In:0:C of the In2O3 films at 150, 170 and 200 °C were 1:1.16:0.04 (InO1.16C0.04), 1:1.16:0.03 (InO1.16C0.03) and 1:1.2:0 (InO1.2), respectively. We found that the carbon-doped (InO1.16C0.04, InO1.16C0.0303) and carbon-free In2O3 (InO1.2) films could be easily deposited by changing the growth temperature. All films had an amorphous structure. The electrical properties of InO1.16C0.04 TFT changed dramatically from metal-like conductor to semiconductor after post-metallization annealing at 150 °C in O3 while no InOi.2 TFT changed. This is thought to be due to the suppression of excess oxygen vacancies in InO1.16C0.04 channel by effect of doped carbon. The InO1.16C0.04-containing TFT exhibited superior characteristics of S.S (0.37 V/dec), Ion/Ioff (1.0x108), Vth. (3.5 V) and saturation field effect mobility (20.4 cm2/Vs). Therefore, carbon-doped In2O3 is a promising material as a channel of a flexible TFT where low temperature formation is essential.