Fabrication Optimization to Improve Performance of Gallium-doped Zinc Oxide Thin Film Transistors

We reported the bottom gate type fully transparent Ga-doped ZnO TFTs fabricated on glass substrate at room temperature. The effect of O-2/Ar ratio during channel layer deposition on the electrical properties of the device was investigated. The results showed that the TFTs fabricated at O-2/Ar ratio of 25/75 exhibited the best characteristic with the saturation mobility of 14.15cm(2)/V.s, the subthreshold swing (SS) of 422mV/dec, the threshold voltage (V-t) of 4.9V and the on/off current ratio of 2x10(7). Futhermore, the effect of post-annealing temperature was studied, too. It turned out the properties of TFTs were improved after post-annealing, and which reached the best after 250 degrees C post-annealing, with the saturation mobility of 262.49 cm(2)/V.s, the subthreshold swing of 138mV/dec, the threshold voltage of 3V and the on/off current ratio of 2x10(9).