d-orbital ordering of oxygen-deficient amorphous and anatase TiO2-x channels for high mobility thin film transistors

Semiconducting behavior in oxygen-deficient amorphous and anatase TiO2-x films prepared by direct current magnetron sputtering was investigated for high mobility oxide thin film transistors (OxTFTs). Rapid thermal annealing (RTA) was found to induce transition from an amorphous to anatase phase in oxygen-deficient TiO2-x channels and was significantly influenced by DC power during sputtering. Compared to the low field effect mobility (mu(FE): 0.57cm(2)/Vs) of OxTFTs with d-orbital ordered amorphous TiO2-x channels, OxTFTs with anatase TiO2-x channels exhibited a higher mobility (mu FE: 1.02cm(2)/Vs) due to an increased amount of free carriers and effective d-orbital ordering. In addition, the oxygen ambient annealing time during the RTA process had a critical effect on Von shift and shallow/deep trap states of anatase TiO2-x-based TFTs. (C) 2013 AIP Publishing LLC [http://dx.doi.org/10.1063/1.4802717]