Reliability of amorphous InGaZnO thin film transistors passivated by polysilsesquioxane-based passivation layer

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 (V_th) shift during positive bias stress (PBS), suppression of the hump effect during negative bias stress (NBS) and a minimal V_th shift (~ - 0.6 V) during negative bias illumination stress (NBIS). These results demonstrate the potential of easy to fabricate polysilsesquioxane-based passivation layers as effective passivation layer materials.