Flexible self-aligned amorphous InGaZnO thin-film transistors with submicrometer channel length and a transit frequency of 135 MHz

Flexible large area electronics promise to enable new devices such as rollable displays and electronic skins. Radio frequency (RF) applications demand circuits operating in the megahertz regime, which is hard to achieve for electronics fabricated on amorphous and temperature sensitive plastic substrates. Here, we present self-aligned amorphous indium-gallium-zinc oxide-based thin-film transistors (TFTs) fabricated on free-standing plastic foil using fabrication temperatures . Self-alignment by backside illumination between gate and source/drain electrodes was used to realize flexible transistors with a channel length of 0.5 µm and reduced parasitic capacities. The flexible TFTs exhibit a transit frequency of 135 MHz when operated at 2 V. The device performance is maintained when the TFTs are bent to a tensile radius of 3.5 mm, which makes this technology suitable for flexible RFID tags and AM radios.