SID Symposium Digest of Technical Papers · 2011 · 16 citations · 12 references
EngineeringMaterials EngineeringMaterials ScienceElectronic MaterialsSemiconductor DevicesThin FilmsMetal-oxide-semiconductor Field-effect TransistorsOptoelectronic DevicesOxide SemiconductorsSemiconductor ReliabilityThin Film Electrical PropertiesThin-film TransistorsBias Stress EffectsDefect DensityOxide Thin-film TransistorsOxygen Vacancy FormationPhotoconductivityPhotoinduced InstabilityThreshold VoltageVisible Light Exposure
Abstract Stress/recovery measurements demonstrate that even high‐performance passivated In‐Zn‐O/ Ga‐In‐Zn‐O thin film transistors with excellent in‐dark stability suffer from light‐bias induced threshold voltage shift (ΔV T ) and defect density changes. Visible light stress leads to ionisation of oxygen vacancy sites, causing persistent photoconductivity. This makes the material act as though it was n‐doped, always causing a negative threshold voltage shift under strong illumination, regardless of the magnitude and polarity of the gate bias.
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