In this study, the effects of soft baking temperature on the solution derived ZTO (Zn-Sn-O) TFTs (thin-film transistors) as a In-free oxide semiconductor were investigated. In spite of the same hard baking at high temperature(600℃), the electrical properties of ZTO TFT was greatly changed by a small difference in soft baking temperature(180~250℃). The performance of TFT was deteriorated as the soft baking temperature increased. Therefore, it is important to remove the water-related defects well as organic impurities from the ZTO films during soft baking for fabrication of solution-derived high performance of TFTs.

l.ao.5Sro5CoO₃ (LSCO) electrode thin films with a resistivity of ~ 1,600 μΩcm were grown on c-Al₂O₃ (0001) substrates. ZnsnO₃ (ZTO) thin films with different thicknesses were directly grown on LSCO/c-Al₂O₃ (0001) substrates at a substrate temperature that ranged from 550 to 750 ℃ using Pulsed Laser Deposition (PLD). The secondary phase Zn₂SnO₄ occurred during the growth of ZTO films and it became more significant with further increasing substrate temperature. Polarization-electrc-field (P-E) hysteresis characteristics. with a remnant polarization and coercive field of 0.05 μC/㎠ and 48 kv/cm, respectively, were obtained in the ZTO film grown at 700℃ in 200 mTorr.

Because the Pb-based piezoelectric materials showed problems such as an environmentalpollution. lead-free ZnSnO3 materials were studied in the present study. The ZnSnO3 thin films weredeposited at 640℃ on Pt/Ti/SiO2 substrate by pulsed laser deposition (PLD) and were annealed for 5 minat 750℃ using rapid thermal annealing (RTA) in nitrogen atmosphere. Samples annealed at 750℃ showeda smooth morphology and an improvement of the dielectric and leakage properties, as compared withas-grown samples. However, electrical properties of the ZnSnO3 thin films obtained in the present studyshould be improved for piezoelectric applications.