Pulsed UV-Assisted Annealing for Low-Temperature Processing of In₂O₃ Thin Films for TFT Applications

In this study, we explore the potential of pulsed ultraviolet (UV)-assisted thermal annealing as an effective low-temperature processing technique for fabricating high-performance indium oxide (In₂O₃) thin films, with a particular emphasis on their application in thin-film transistors (TFTs). In₂O₃ films were synthesized using a solution-based method, with indium nitrate hydrate serving as the precursor. The precursor solution was spin-coated onto SiNx/p⁺–Si substrates to form uniform thin films. To assess the effectiveness of the annealing approaches, we compared conventional thermal annealing at 300 °C with pulsed UV-assisted thermal annealing conducted at a reduced temperature of 200 °C. Characterization techniques—including UV–Vis spectroscopy, X-ray diffraction, atomic force microscopy, and scanning electron microscopy—revealed that pulsed UV-assisted annealing significantly improved the optical transparency, crystallinity, and carrier concentration of the films, even at lower processing temperatures. Electrical characterization of the resulting TFTs showed enhanced device performance, including higher drain currents and improved field-effect mobility, compared to devices fabricated with conventionally annealed films. Despite the improved electrical properties, the increased hydrophilicity of the UV-annealed films indicates the need for additional surface passivation to ensure long-term device stability. Overall, this work demonstrates that pulsed UV-assisted thermal annealing is a promising low-temperature processing strategy for the development of transparent oxide semiconductors in next-generation electronic devices.