Enhancement of electrical properties of a-IGZO thin film transistor by low temperature (150 °C) microwave annealing for flexible electronics

Abstract

A relatively low-temperature process is required to fabricate amorphous oxide thin film transistor (TFT) display backplanes for flexible electronics. However, in order to ensure the outstanding electrical property of TFT, a typical post-annealing process should be performed at 300 °C or above. This is not compatible with flexible substrates in the process. In our work, we applied microwave annealing (MWA) at a low-temperature (150 °C) to the oxide TFT and verified its feasibility through the evaluation of various electrical properties. Even an a-IGZO TFT by MWA at such a low-temperature shows high mobility (29.0 cm2/V s) by DC ID-VG measurement, which is 4 ∼ 5 times higher than other counterparts, indicating that the MWA process is very effective to minimize the defects in an oxide semiconductor channel. To further investigate the intrinsic mobility of TFT with negligible charge trapping, we carried out fast and pulse ID-VG measurement methods. The intrinsic mobility extracted from this measurement is found to be 35.3 cm2/V s, 21.7% higher than that of DC ID-VG. We are expecting that the low-temperature MWA process would be widely used for the process of oxide TFT in a flexible platform.