Photolithography-free fabrication of a-IGZO thin film transistor with interconnecting metal lines

Abstract

Amorphous indium-gallium-zinc-oxide (a-IGZO) thin film transistor (TFT) was successfully fabricated by the imprint lithography and plasma etching processes without using a photolithography process. The TFT is provided with two horizontally and vertically crossed electrode lines. In order to isolate the horizontal electrode line on the bottom surface, fine holes were drilled in the top vertical electrode line to separate the bottom electrode line. A 50 × 50 μm2 channel-sized TFT with connecting metal lines was completed easily using one imprint process and continuous etching process in one chamber. The TFT exhibited a linear mobility of 14.5 cm2/Vs, and a current on/off ratio of 2.07 × 105 at the drain voltage of 0.5 V. Since this TFT fabrication method utilizes self-aligned imprint lithography, there is no difficulty in alignment when using photolithography, and it can be utilized as a more complex and fine TFT array fabrication process through process improvement.