We report fabrication of an amorphous TiO2-x (a-TiO2-x) channel based oxide thin film transistor (OxTFT) by direct-current magnetron sputtering using an oxygen-deficient TiO2 (x) target. By rapid thermal annealing of a sputtered TiO2 (x) channel layer in nitrogen ambient, we obtained a-TiO2-x-based OxTFTs with a performance of mu(FE) of 0.69 cm(2)/Vs, I-on/off of 2.04 x 10(,)(7) SS of 2.45 V/decade and V-T of 10.45 V. X-ray photoelectron spectroscopy showed that the a-TiO2-x-based OxTFT performance could be attributed to the oxygen-deficient TiO2-x channel layer, which has a multiplicity of Ti oxidation states such as Ti2+, Ti3+ and Ti4+ unlike stoichiometric TiO2 film. This indicated that the sputtered a-TiO2-x channel layer is a promising indium-free or gallium free oxide channel layer that could substitute for high-cost indium or gallium oxide based channel layers to generate cost-efficient OxTFTs. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3589983] All rights reserved.