2018 iMiD, Busan, Korea

2018 iMiD, Busan, Korea

August 28 - 31, 2017 (Tue. - Fri.), Exhibition Center I, BEXCO 

Coplanar a-InGaZnO Thin Film Transistors with Photo-Patterned Ionic-Polymer Gate Dielectric

Dayoon Lee, Yongchan Kim, and Hojin Lee

 

 Abstract

Currently electrolyte-gated thin-film transistors (TFTs) have been actively studied due to their advantages of high-density carrier accumulation in the channel, ultra-low operation voltage, and low-temperature process. For patterning the electrolyte to be used as a gate dielectric, there have been many different approaches reported so far, such as ‘cut and stick’ method, aerosol printing process, or using additional mold to isolate the ionic liquid. However, most of previous methods have challenges on realizing micron-sized fine patterns. In this paper, we adopted photo-patternable ionic-polymer as a gate dielectric for coplanar TFT structures where the gate, source, and drain electrodes deposited by single lift-off process. After electrodes and a-InGaZnO active layer was patterned in sequence, photo-patternable ionic polymer dielectric was patterned using photo cross-linking reactions to UV light. The measured transfer characteristics of the fabricated TFTs are shown in Fig. 1. According to measurement results, we confirmed the high field-effect mobility (~4.36 cm²/V·s), high on-off ratio (~10⁶), and good sub-threshold swing (~108 mV/decade) could be achieved at drain voltage of 1V.