Thermal Annealing Improved Stability of Amorphous InGaZnO Thin-Film Transistors Under AC Bias Stresses

Abstract

Amorphous InGaZnO (a-IGZO) thin-film transistors (TFTs) severely degrade under AC gate bias stress and AC drain bias stress, whose transfer curves respectively undergo positive shifts of 6.3 and 14.2 V after a stress time of 3000 s with a stress amplitude of 20 V. In this study, annealing at 400 °C in O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> atmosphere is performed to effectively reduce the acceptor-like trap states in the a-IGZO channel and the electric field in the etching-stop layer under the extended drain electrode, which participate in dynamic and DC degradation mechanisms, respectively. Thus, a-IGZO TFTs exhibiting excellent stability without any shift of the transfer curve under the same AC gate bias stress and AC drain bias stress are experimentally demonstrated simultaneously.