Investigation of Polysilazane-Based $\hbox {SiO}_{2}$ Gate Insulator for Oxide Semiconductor Thin-Film Transistors

To realize all-solution-processed oxide semiconductor thin-film transistors (TFTs), for use in display applications in particular, a polysilazane-based SiO₂ gate insulator is investigated. The gate leakage current was reduced to 1 × 10^-8 A/cm² at 1 MV/cm. TFTs were successfully fabricated using a ZrInZnO precursor solution for the active layer and a polysilazane-based solution for the gate insulator. A smooth interface without defects was confirmed in the ZrInZnO/SiO₂ system. The resulting TFTs exhibited a field-effect mobility of 19-29 cm²·V^-1·s^-1 with a low leakage current of less than 9 × 10^-11 A. These results are very promising for the development of all-solution-processed oxide semiconductor TFTs, which have the potential to replace TFTs fabricated by vacuum deposition methods.