Degradation of a-IGZO Thin-Film Transistors Under Negative Bias and Illumination Stress in the Time Span of a Few Seconds

This letter investigated the time response behavior of amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs) under negative gate bias and illumination stress (NBIS) in sub-seconds. For the first time, significant degradation even in periods as short as sub-seconds under NBIS was observed. The stretched-exponential behavior of threshold voltage shift (ΔVth) revealed similar mechanisms for short- and long-term NBIS. As a-IGZO TFTs operate at a very high speed, the nonnegligible ΔVth owing to the influence of fast oxygen vacancy needs to be considered to ensure a-IGZO TFT circuits function well in real applications.