Reliability Enhancement of Solution Processed Amorphous In-Zn-O Thin-Film Transistors via a Low Temperature (180 °C) Solution Processed Passivation

Abstract

The interaction between ambient environment or the adsorption-desorption of oxygen and water molecules at the back channel of bottom gate amorphous InZnO (a-IZO) thin-film transistors (TFTs) is one of the biggest issues that greatly affects the performance and reliability of TFTs. The issue can be overcome by depositing a passivation at the back channel as a protection barrier. This paper presents the performance of solution processed a-IZO TFTs incorporated with different types of Polysilsesquioxane (PSQ) passivation layers fabricated at low temperatures of 180 °C. A clear reliability enhancement is observed by using the low temperature PSQ which reduced the very high threshold voltage shift ($V_{th}$) of 16.0 V after positive bias stress (PBS) of unpassivated a-IZO TFT to a low $V_{th}$ of 3.1 V after passivation.