16.4: Photostability Improvement of a-InGaZnO TFTs by Introducing a Transparent UV Shielding Layer

The photosensitivity and stability of a‐IGZO TFTs can be efficiently improved by introducing a transparent passivation layer made of Mo‐doped ZnO (MZO). Under a negative bias illumination stress (NBIS) with photoenergy (∼3.4eV), the ΔVth of MZO‐passivated TFTs was 0.39 V after 5400 sec of NBIS, whereas the unpassivated TFTs showed a large ΔVth of −10.56 V. Moreover, the unpassivated TFTs exhibited a slight positive Vth shift of 1.69 V after 5400 sec of positive bias stress (PBS), while the ΔVth of MZO‐passivated TFTs was only 0.45 V.