Transparent IGZO-Based Logic Gates

Optically transparent indium-gallium-zinc-oxide-based nand and nor gates and inverters were fabricated and characterized using transistors deposited at room temperature with 5-, 10-, and 20-μm gate lengths and beta ratio between 2.5 and 40. The nand and nor gates´ operation frequencies were measured up to 5 kHz. The individual transistors were measured to have saturation mobility of 14 cm²/V ·s, subthreshold swing of 190 mV/dec, and current on/off ratios in excess of 10⁸. Logic operations were satisfactorily demonstrated for bias voltage between 1 and 20 V. These results indicate that viable digital logic can be applied particularly where optical transparency or the use of novel flexible substrates is more important than the operating speeds.