To investigate TFT device performance based on IZTO semiconductor channel layer, the transistor prepared using heavily-doped silicon wafer substrate was examined in n-channel mode. Figure 4 depicts the transfer characteristic of IZTO TFT device deposited by RF magnetron sputtering with annealing temperature variation. It is seen that field effect mobility (μFE), on/off current ratio (Ion/off), and subthreshold swing (SS) values improved as annealing temperature increased from 150 °C to 350 °C, as shown in Table 4. Threshold voltage (VT) value tended to shift to zero voltage by controlling the carrier concentration of IZTO channel layer with the increasing annealing temperature. As the carrier concentration increased, the threshold voltage and subthreshold swing values shifted to more desirable values . The enhancement of TFT performance was noticed by lowering resistivity and reducing SS values of IZTO channel layer with increasing annealing temperature, which might be mainly due to oxygen diffusion from IZTO layer and rearrangement of molecular bonding during annealing process, thus inducing the acceleration of electrons to pass through channel region between source and drain .