Inkjet-printed and deep-UV-annealed YAlOx dielectrics for high-performance IGZO thin-film transistors on flexible substrates

Bolat, S.; Fuchs, P.; Knobelspies, S.; Temel, O.; Torres Sevilla, G.; Gilshtein, E.; Andres, C.; Shorubalko, I.; Liu, Y.; Tröster, G.; et al.

Adv. Electron. Mater. (2019).

https://doi.org/10.1002/aelm.201800843

Abstract

Recent developments in inkjet printing have proven it a viable method for low-cost and large-area coating of oxide materials. The main drawback of this method is the common requirement of a post-deposition annealing (PDA) of the printed layers at relatively high temperatures (T > 200 °C). This sets a requirement for the substrate to have high glass transition temperature (Tg). To reduce the PDA temperature, deep-ultraviolet (DUV) annealing is proposed as an effective method. In this study, yttrium aluminum oxide (YAlOx) dielectrics are realized for application in flexible electronic devices via inkjet printing and DUV annealing at a temperature of 150 °C. The effect of the Y concentration on the electrical properties of the dielectrics is investigated. An increase in the Y incorporation is found to increase the dielectric constant and decrease the leakage current of the dielectrics. Flexible indium gallium zinc oxide (IGZO) thin-film transistors with 50 μm channel widths and 7 μm channel lengths employing printed YAlOx dielectrics are fabricated on polyimide substrates with a maximum processing temperature of 150 °C, yielding a maximum gate leakage current of 10–13A, a high ION/IOFF ratio of 108, and a field effect mobility of 4.3 cm2 V–1 s–1.