Optimization of RF Sputtering Power for High-Performance ITZO Thin-Film Transistors: Correlation Between Film Properties, Oxygen Defects and Electrical Performance

This study investigates the optimization of RF sputtering power for high-performance ITZO TFTs by correlating the film physicochemical properties, oxygen-related defects, and device characteristics. The films were used as the channel layer in thin-film transistors (TFTs). XRD, UV–Vis spectroscopy, and XPS were systematically used to investigate the effects of sputtering power on the film structure, optical properties, chemical composition, and electrical performance of the devices. The results show that X-ray diffraction (XRD) analysis revealed that the ITZO films prepared at different sputtering powers were predominantly amorphous in structure. UV–Vis measurements indicated that the ITZO films maintained a high optical transmittance (>85%), demonstrating their strong potential for application in transparent electronic devices. X-ray photoelectron spectroscopy (XPS) analysis further showed that the sputtering power affected the chemical states of In, Sn, Zn, and O elements, as well as the concentration of oxygen vacancies in the films. Appropriately increasing the sputtering power was found to help regulate the carrier concentration and defect states of the films. When the sputtering power was 70 W, the ITZO TFT exhibited superior electrical performance, with a saturation mobility of 8.46 cm2·V−1·s−1, a threshold voltage of 1.86 V, a subthreshold swing of 0.29 V/decade, and an on/off current ratio of 4.50 × 109.