High-Performance Solution-Processed InGaZnO Thin-Film Transistor Fabricated by Ozone-Assisted Atmospheric Pressure Mist Deposition

High-performance amorphous indium-gallium-zinc oxide thin-film transistors (IGZO TFTs) were demonstrated at 360 ^°C with the IGZO channel and aluminium oxide (AlOx) gate dielectric stack that was deposited by ozone (O₃)-assisted atmospheric pressure chemical vapor deposition (AP-CVD) using an ultrasonic atomized solution mist. The AlOx gate dielectric with a breakdown electric field of over 8 MV/cm and dielectric constant of 7.0 was obtained. In addition, the introduction of O₃ oxidant during the IGZO deposition decreases the carbon and hydrogen contamination in the film. Field effect mobility and the sub-threshold swing of the IGZO TFT with AP-deposited IGZO/AlOx stack were significantly improved to 7.5 cm² / Vs and 0.38 V/dec, respectively, by the O₃ oxidant introduced in the IGZO and AlOx depositions. The O₃ oxidant is very effective in improving the electrical properties of solution-processed oxide TFTs.