Atomic Structure Evaluation of Solution-Processed a-IZO Films and Electrical Behavior of a-IZO TFTs

Understanding the chemical reaction pathway of the metal–salt precursor is essential for modifying the properties of solution-processed metal-oxide thin films and further improving their electrical performance. In this study, we focused on the structural growth of solution-processed amorphous indium-zinc-oxide (a-IZO) films and the electrical behavior of a-IZO thin-film transistors (TFT). To this end, solution-processed a-IZO films were prepared with respect to the Zn molar ratio, and their structural characteristics were analyzed. For the structural characteristic analysis of the a-IZO film, the cross-section, morphology, crystallinity, and atomic composition characteristics were used as the measurement results. Furthermore, the chemical reaction pathway of the nitrate precursor-based IZO solution was evaluated for the growth process of the a-IZO film structure. These interpretations of the growth process and chemical reaction pathway of the a-IZO film were assumed to be due to the thermal decomposition of the IZO solution and the structural rearrangement after annealing. Finally, based on the structural/chemical results, the electrical performance of the fabricated a-IZO TFT depending on the Zn concentration was evaluated, and the electrical behavior was discussed in relation to the structural characteristics.