Applied Physics Letters · 2009 · 171 citations · 18 references
EngineeringElectrical EngineeringMaterials ScienceMicroelectronicsSemiconductor DevicesThin FilmsAmorphous Electronic MaterialsDielectricsMetal-oxide-semiconductor Field-effect TransistorsSemiconductor Thin FilmsThin-film MaterialsThin-film TransistorsAmorphous Indium Gallium Zinc OxideCharge TrapsGate Dielectric EngineeringGate DielectricsOxide Thin-film TransistorsThreshold VoltageThreshold Voltage StabilityTraps
We investigated the threshold voltage (Vth) instability for various gate dielectrics (SiNx and SiOx) in amorphous indium-gallium-zinc oxide (a-IGZO) thin film transistors (TFTs). The a-IGZO TFTs with SiNx 150 °C exhibited reasonable electrical performance (field-effect mobility of 8.1 cm2/V s and Ion/off ratio of >108) but showed huge Vth shift under positive gate bias. The TFTs with SiOx dielectrics exhibit smaller Vth instability than those of SiNx dielectrics. This behavior can be explained by using simple charge trapping into the gate insulators and the difference of Vth instability on various dielectrics may be originated from the hydrogen contents, providing high density of charge traps in gate dielectrics.
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