Eco-Friendly Fully Water-Driven HfGdOx Gate Dielectrics and Its Application in Thin-Film Transistors and Logic Circuits.

In this work, HfGdO_x gate dielectric thin films have been prepared via a nontoxic and environmental-friendly fully water-driven (WD) method. An in-depth investigation has been conducted to reveal the evolution of physical properties in the as-prepared HfGdO_x thin films as a function of annealing temperature. Based on the measurements of electrical parameters of the HfGdO_x thin films, it is observed that the 500 °C-annealed HfGdO_x thin films have shown optimized properties, including a smooth surface, lower leakage current density, and a larger areal capacitance. To validate the feasibility of the HfGdO_x gate dielectrics in thin-film transistors (TFTs), In₂O₃/HfGdO_x TFTs have been constructed. The optimized In₂O₃/HfGdO_x TFT exhibited excellent electrical performances, including high field-effect mobility of 11.2 cm² V⁻¹ s⁻¹, a high ON-/OFF-state current ratio of 4.1 × 10⁶, a small sub-threshold swing of 105.2 mV/decade, and a threshold voltage shift of 0.58 V after 7200-s bias stress, respectively. Finally, based on the In₂O₃/HfGdO_x TFT, an inverter is assembled by connecting an external 3-MΩ resistor. High gain of 8.73 and excellent swing characteristics have been obtained. As a result, it can be inferred that fully WD In₂O₃/HfGdO_x TFTs with high performance will pave the way for achieving low-power-consumption, low-cost, and large-area electronics. [ABSTRACT FROM AUTHOR]