Investigation on the effect of contact annealing on the electrical properties of a-IGZO TFTs for LTPO AMOLEDs

Abstract Amorphous IGZO TFTs play a critical role in low-temperature polycrystalline oxide (LTPO) technology, enabling energy-efficient AMOLED displays and next-generation flexible electronics. However, their intrinsic instability, mainly caused by oxygen vacancies, often leads to high threshold voltage and poor device reliability, limiting further advancements in AMOLED power efficiency and long-term stability. In this work, we propose a Controlled Annealing Process (CAP) to enhance the electrical stability of IGZO TFTs. By optimizing annealing temperature and duration, we effectively suppress oxygen vacancies, as confirmed by XPS and energy band analysis. Devices annealed at 400 °C for 30 minutes exhibit minimal threshold voltage shift (<0.1 V) and improved subthreshold swing and on/off ratio. This method offers a practical route toward low-Vth and reliable IGZO TFTs for high-performance AMOLED applications.