Flexible Thin Film Transistor (TFT) and Circuits for Internet of Things (IoT) based on Solution Processed Indium Gallium Zinc Oxide (IGZO)

Abstract

Solution-processed metal oxide semiconductors are being extensively studied as a channel material for active semiconductor transistors. Among all metal oxide semiconductors, indium-gallium-zinc-oxide (IGZO) gained considerable attention for thin film transistors (TFTs) due to its promising electrical properties. Although metal oxide TFTs fabricated with vacuum deposition techniques enjoy the advantage of higher mobility in comparison with solution processing. However, vacuum deposition techniques are very costly due to expensive equipment, restricting its usage for emerging modern technologies, such as printed and flexible electronics. On the other hand, solution-processed metal oxide devices have an added advantage, such as low cost, compatibility with flexible substrates. Therefore, developments of solution processed metal oxide TFTs on flexible substrates could open a new era of flexible and wearable electronics. Herein, we report the fabrication of flexible thin film transistors (TFT) and inverter circuit using solution-processed indium-gallium-zinc-oxide as a channel material by uniting with room temperature deposited anodized high-K aluminium oxide (Al2O3) for gate dielectrics. The flexible TFTs operates at low voltage Vds of 4 V, with threshold voltage Vth 1.05 V along with hysteresis as low as 0.4 V. The extracted electron mobility (µ) at saturation regime, is 4.77 cm2/V.s. The transconductance, gm, is 90.8µS, subthreshold swing (SS) 357 mV/dec and on/off ratio 105.