Stably Saturated Output Current Characteristics and Hot-Carrier Reliability of a-InGaZnO Thin-Film Transistors With Source-Connected Field Plate

In this study, the electrical characteristics and hot-carrier reliability are investigated in via-contact type amorphous indium-gallium-zinc oxide thin-film transistors (TFTs) with different field-plate structures, generally used as a light-shielding layer. Compared to a conventional symmetric structure, the output current characteristics of the asymmetric structures with a source-connected (drain-connected) field plate are more saturated (unsaturated). The source-connected field plate (SCFP) structure exhibits a good channel control ability, which can effectively suppress the drain-induced barrier-lowering effect and improve the IR-drop phenomena to achieve uniform brightness in each pixel over a large-area display. In addition, this structure demonstrates a good hot-carrier stress (HCS) stability confirmed by simulations and energy bands analysis. Based on the results of this study, it is proposed that the SCFP structure with stably saturated output current characteristics and HCS reliability is suitable for driving TFTs in active-matrix organic light-emitting diode (AM-OLED) applications.