The improved properties of solution-based InGaSnO (IGTO) thin film transistor using the modification of InZnO (IZO) layer

For improving the properties of indium-gallium-tin oxide (IGTO) thin film transistors (TFTs) based on solution method, indium-zinc oxide (IZO) thin film was used as a modification layer. When IZO did not perform post-annealing, the performance improvement of bilayer TFTs was not significant. When IZO performed post-annealing, the performance improvement of the bilayer TFTs was obvious. We also compared the effects of annealing time on the performance of IGTO TFTs. The modifying effects of IZO and the suitable annealing time led to a great improvement in the performance of TFTs. The mobility was increased by about 10 times than monolayer IGTO (0.27 cm²V⁻¹s⁻¹→4.38 cm²V⁻¹s⁻¹), and the threshold voltage and subthreshold swing were also very small (0.60 V, 0.55). We attribute the performance improvement of dual active layer TFTs to two reasons. On the one hand, the modifying effects of IZO made the IGTO defect state less and the film denser. On the other hand, the bilayer TFTs form a heterojunction structure similar to 2-dimensional electron gas (2DEG), which enhanced the mobility of the TFTs. This paper provides a research basis for the process of preparing dual active layers by solution method, and provides a new idea for the performance improvement of IGTO.