The effects of a combined thermal treatment of substrate heating and post-annealing on the microstructure of InGaZnO films and the device performance of their thin film transistors

This study examined the possibility of engineering the microstructure of InGaZnO films and enhancing the device performance of their thin film transistors by combining the thermal treatments of substrate heating and post-annealing. Microstructure characterization using high-resolution transmission electron microscopy and energy-filtered selected area electron diffraction helped us to unravel a systematic improvement in atomic order induced by substrate heating. Hall measurement analysis confirmed that the electrical properties (carrier concentration and electron mobility) varied very sensitively with the thermal treatments. The combined thermal treatments were found to effectively enhance the overall device performance of the transistors, and the sample deposited at 200 °C and post-annealed at 400 °C showed the best transistor characteristics with a saturation mobility (msat) of nearly 26 cm²/V s.