Thin film transistor using amorphous InGaZnO films as both channel and source/drain electrodes

For the fabrication of a low-cost and transparent amorphous InGaZnO (a-IGZO) thin film transistor (TFT), the possibility of using semiconducting and conducting, a-IGZO films as the channel and source/drain (S/D) electrode layers, respectively, was investigated, as was their effect on the device performance. Although the a-IGZO S/D electrodes' transistor performance was somewhat degraded, possibly due to the ex-situ integration process, acceptable TFT characteristics and transparency were obtained for the next-generation, transparent active matrix displays. The post-fabrication annealing ambient significantly affected the electrical properties of the a-IGZO S/D and channel layers, as the carrier concentration exhibited a close dependency on the amount of oxygen in the annealing ambient.