Anomalous Stress-Induced Hump Effects in Amorphous Indium Gallium Zinc Oxide TFTs

In this paper, we investigated the anomalous hump in the bottom gate staggered a-IGZO TFTs. During the positivebias stress, a positive threshold voltage shift was observed in the transfer curve and an anomalous hump occurred asthe stress time increased. The hump became more serious in higher gate bias stress while it was not observed underthe negative bias stress. The analysis of constant gate bias stress indicated that the anomalous hump was influencedby the migration of positively charged mobile interstitial zinc ion towards the top side of the a-IGZO channel layer.