Self-aligned imprint lithography process for fabricating indium-gallium- zinc-oxide thin film transistor arrays

A 5 × 5 amorphous indium-gallium-zinc-oxide (a-IGZO) thin film transistor (TFT) array was successfully fabricated using a self-aligned imprint lithography (SAIL) process. This SAIL is a top-down process in which various TFT materials are pre-formed in multilayers and then unwanted areas are removed by plasma etching using a three-dimensional etch mask to fabricate the device. The fabrication of an a-IGZO TFT array using the SAIL process involves only a single imprint process followed by several successive plasma etching processes. Because SAIL does not require a photolithography process, there is no alignment error and uniform TFT arrays can be easily fabricated at a very high speed. The linear mobility of the 25 TFTs in the 5 × 5 a-IGZO TFT array fabricated using SAIL was 13.8 ± 1.53 cm2/V‧s at a gate voltage of 20 V. The average on/off ratio and threshold voltages were 3.92 × 106 and − 8.58 V, respectively, and showed uniform characteristics across 25 TFTs. The SAIL process, which does not require a photolithography process, is suitable for roll-to-roll processing using plastic substrates and can be used in the future to manufacture not only a-IGZO TFT arrays but also various other devices.