Improved negative bias stress stability of IZO thin film transistors via post-vacuum annealing of solution method

Post-vacuum-annealed amorphous indium zinc oxide (a-IZO) nanostructure thin-film transistors (TFTs) were fabricated by a simple solution-based method. The number of oxygen-related defects in the IZO films was reduced by post-vacuum annealing, as revealed by X-ray photoelectron spectroscopy results. The refractive index studies of as-prepared films indicate the reduced film surface porosity. With the optimal post-vacuum treatment temperature of 250°C, the field-effect mobility and subthreshold slope (S) of TFTs (2.81 cm²/V s and 0.72 V/dec, respectively) improved compared to those of as-prepared IZO TFTs (0.38 cm²/V s and 3.79 V/dec, respectively). The negative bias stress tests of the vacuum-annealed devices was enhanced relatively high electrical stability due to fewer oxygen deficiencies in the IZO films.