Supreme Performance of Zinc Oxynitride Thin Film Transistors via Systematic Control of Photo-Thermal Activation Process
Abstract
Zinc oxynitride (ZnON) is a relatively novel class of material, often regarded as a promising alternative to oxide semiconductors owing to its relatively high electron mobility and low concentration of oxygen-related defects that affect the device reliability. In the present study, the thermal annealing of ZnON for thin film transistor (TFT) applications is performed in conjunction with a source of ultraviolet (UV) radiation. The oxygen radicals and ozone produced in this process appear to oxidize surface the surface of ZnON thin film. As the annealing temperature increases in the presence of UV light, chemically stable ZnO and non-stoichiometric ZnxNy bonds are formed without significant change in oxygen/nitrogen ratio within the film. Such a phenomenon is accompanied with decreased field effect mobility and device stability under positive bias stress. Under optimized photo-thermal annealing conditions (150°C), ZnON TFTs exhibit a high field effect mobility of approximately 52.5 cm2/Vs and reasonable stability under positive bias stress.