The annealing effects on the properties of solution-processed alumina thin film and its application in TFTs

Solution-processed AlOx thin films were annealed at different temperatures (250, 350, 450 and 550 °C). The annealing effects on the physical properties of AlOx thin films were studied. It is found that the leakage current density is decreased with increasing annealing temperature. The AlOx thin film annealed at 550 °C exhibits the best insulation performance with a current density of 2.7×10−9 A/cm2 at a bias voltage of 3 V. In order to demonstrate the feasibility of application in the thin film transistor (TFT) devices, an indium–titanium–zinc-oxide TFT based on AlOx dielectric was integrated. The TFT can be operated under a low voltage of 5 V, with a high field effect mobility of 23.7 cm2/Vs, a threshold voltage of 1.5 V, a subthreshold swing of 0.22 V/decade, and an on/off current ratio of 106. The results demonstrate that AlOx dielectric thin film prepared by solution process is a promising gate dielectric candidate for high-performance oxide devices. The results indicated the potential applications in transparent electronics.