Solution-Processed SrOx-Gated Oxide Thin-Film Transistors and Inverters

In this paper, high-k strontium oxide (SrOx) dielectric thin films were fabricated using simple and low-cost solution process. The formation and properties of SrOx thin films annealed at various temperatures (400 degrees C, 500 degrees C, 600 degrees C, and 700 degrees C) were investigated using numbers of characterization techniques. The electrical analysis indicates that the insulating properties of SrOx thin films were improved with increasing annealing temperature. The post-annealing at temperatures higher than 400 degrees C enables the SrOx thin film, exhibiting low-leakage current density of similar to 10(-8) A cm(-2) at 3 V and the areal capacitance larger than 350 nF cm(-2) at 20 Hz. To further explore the possible applications of solution-processed high-k SrOx thin films for thin-film transistors (TFTs), the indium oxide (In2O3) TFTs based on SrOx thin films were integrated for testing. The optimized In2O3/SrOx TFT exhibits high performance with an average field-effect mobility of 5.61 cm(2) V-1 s(-1), a small subthreshold swing of 110 mV dec(-1), and a large on/off current ratio of 107. To demonstrate the potential of In2O3/SrOx TFT toward more complex logic applications, the unipolar inverter was further constructed and exhibited a high gain of 9.7. Importantly, all these device parameters were obtained at an ultralow operating voltage of 3 V, which represents a step toward portable, battery-driven, and low-power consumption electronics and circuits.