Highly Reliable Polysilsesquioxane Passivation Layer for a-InGaZnO Thin-Film Transistors

Abstract

We report the fabrication of highly reliable amorphous InGaZnO (a-IGZO) passivated by a polysilsesquioxane-based passivation layer using a simple solution process. Results show that a copolymer of methylsilsesquioxane and phenylsilsesquioxane is an effective passivation layer. a-IGZO thin film transistors (TFT) passivated by this copolymer showed a small threshold voltage (Vth) shift of 0.1 V during positive bias stress, very small Vth shift of less than 0.1 V during negative bias stress and a minimal Vth shift (∼ −2.4 V) during negative bias illumination stress. These results demonstrate the potential of easy to fabricate polysilsesquioxane-based passivation layers as effective passivation materials.