Transparent Al–In–Zn–O Oxide semiconducting films with various in composition for thin-film transistor applications

Al–In–Zn–O thin-film transistors were fabricated. To examine the effect of In composition, we adopted a co-sputtering method using Al–Zn–O and In2O3 targets. The sputtering power of In2O3 was varied to 200, 150, and 50 W. The mobility and turn-on voltage of each device were 27.8 cm2V−1 s−1 and −4.2 V, 4.5 cm2V−1 s−1 and −3.5 V, 0.7 cm2V−1 s−1 and −3 V, respectively. We also investigated instabilities under negative gate bias stress (NBS) and negative bias illumination stress (NBIS). While the NBS was not influenced by the In contents, the NBIS characteristics were optimized for the device with In2O3 sputtering at 150 W.