Effects of Tensile Strain on Dynamic and Static Inverters Using Amorphous Indium-Gallium-Zinc-Oxide TFTs

The dynamic inverter using amorphous indium-gallium-zinc oxide thin-film transistors (a-IGZO TFTs) is revealed to be more robust to tensile strain than the static inverter that is most widely used in TFT circuits. The results with the inverters can be reasonably extended to NAND or NOR gates, because all of them are commonly composed of pull-up and pull-down networks. The experimental results after tensile bending up to 20 000 times with a bending radius of 1.5 mm show that AVOH and AVOL in the dynamic inverter decrease to 85% and 0% of those in the static inverter, respectively. Also, while the power consumption of the static inverter increases by 36%, which is tens of μA, the dynamic inverter maintains low-power consumption, which is tens of nA. It is also worth noting that ratioed design and TFT operation in the saturation region make the circuit more sensitive to tensile strain than ratio-less design and TFT operation in the triode region.