In-Plane-Gate Oxide-Based Thin-Film Transistors Self-Aligned on Stacked Self-Assembled Monolayer/ $\hbox {SiO}_{2}$ Electrolyte Dielectrics

Low-voltage oxide-based thin-film transistors (TFTs) gated by stacked self-assembled octadecylphonic acid (ODPA) monolayer/SiO₂ electrolyte with an in-plane-gate structure are self-aligned by one nickel shadow mask at room temperature. The stacked gate dielectrics show a reduced gate leakage current with the aid of the well-organized dense-stacked ODPA monolayer buffer. The equivalent field-effect mobility, subthreshold voltage swing, and drain current on/off ratio of such TFTs are estimated to be 11 cm²/V·s, 140 mV/dec, and 10⁶, respectively. Such low-voltage in-plane-gate TFTs are very promising for low-cost portable sensors.