Effects of Alternating Pulse Bias Stress on Amorphous InGaZnO Thin Film Transistors

Abstract

Amorphous InGaZnO (a-IGZO) TFTs attracted more demands due to the transparency and high mobility. Since TFTs are always exposed to both positive and negative gate bias, the alternating pulse bias stress tests are required to ensure stable TFT characteristics. In this paper, the effects of alternating pulse bias stress on the threshold voltage shift (ΔVth) of a-IGZO TFTs with respect to the channel length (L) and the stress time interval (Tinterval) are investigated using the concepts of the stretched-exponential function and the density of total trap states (NT).