Top-gate effects in dual-gate amorphous InGaZnO_4 thin-film transistors

摘要

We discuss the dependence of bottom-gate transfer characteristics (V_(bg)-I_d) on top-gate voltage (V_(tg)), which we call "top-gate effects", using a-IGZO TFTs having a dual-gate structure. We consider the top-gate effects to be a measure of how a-IGZO TFT characteristics are sensitive to charge generation on TFTs. We compare the top-gate effects in a-IGZO TFTs and conventional channel-etched a-Si:H TFTs. We found that the positive top-gate effect in a-IGZO TFTs varied depending on top-channel properties, while the negative top-gate effect had a similar impact on V_(bg)-I_d characteristics irrespective of top-channel properties. We also found that a-IGZO TFTs had more significant top-gate effects than conventional a-Si:H TFTs.