Effects of Oxygen Plasma Power on Electrical Characteristics in Multi-Stacked Indium Zinc Oxide Transistors

We report on a method for fabricating solution-processed triple-multi-stacked indium zinc oxide (IZO) thin-film transistors (TFTs) at a low annealing temperature using an oxygen plasma treatment technique at different RF power levels of 120 W, 150 W, 180 W, and 210 W. The oxygen plasma post-treatment is an additional process to optimize the surface state of IZO films and to improve the electrical performance of the TFT device after using a low-temperature solution process instead of a high-temperature annealing process. The plasma-treated TFT device exhibits improved electrical performance, with mobility of 5.1 ± 0.5 cm2/Vs, an on/off ratio of 2.5 × 108, a threshold voltage of 2.6 ± 1.3 V, and a subthreshold swing of 0.6 ± 0.1 V/dec when the RF power is 150 W. Therefore, the multi-stacked activity structure and the low RF power plasma post-treatment process provides a simple and efficient fabrication method that reduces the processing temperature, improves the electrical properties, and can be widely used in flexible electronic devices. Schematic diagrams of the multi-stacked IZO TFT structure, and the oxygen plasmaradiation process with variation of oxygen vacancy before and after treatment.