Inkjet‐Printed and Deep‐UV‐Annealed YAlO_x Dielectrics for High‐Performance IGZO Thin‐Film Transistors on Flexible Substrates

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 (T_g). To reduce the PDA temperature, deep‐ultraviolet (DUV) annealing is proposed as an effective method. In this study, yttrium aluminum oxide (YAlO_x) 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 YAlO_x 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 I_ON/I_OFF ratio of 10⁸, and a field effect mobility of 4.3 cm² V⁻¹ s⁻¹.