双栅非晶InGaZnO薄膜晶体管有源层厚度对电学性能的影响

Effects of Active Layer Thickness of Dual-Gate Amorphous InGaZnO Thin Film Transistors on Their Electrical Characteristics

双栅非晶InGaZnO薄膜晶体管(DG a-IGZO TFTs)具有比单栅a-IGZO TFTs更优良的电学性能.文中基于a-IGZO/SiO_2界面缺陷态呈指数型分布的模型,讨论了在界面缺陷态影响下双栅驱动的DG a-IGZO TFTs有源层厚度对电学性能的影响.研究结果表明:随着有源层厚度的减小,双栅驱动模式下DG a-IGZO TFTs两栅极的耦合作用增强,有源层上、下表面的导电沟道向体内延伸,使器件的场效应迁移率显著增加;界面缺陷态对DG a-IGZO TFTs场效应迁移率的影响随着有源层厚度的减小而降低,对亚阈值摆幅的影响随着有源层厚度的减小而增大.

Dual-gate amorphous InGaZnO thin film transistors （DG a-IGZO TFTs） have better electrical characte- ristics than single-gate a-IGZO TFTs. In this paper, on the basis of a model describing the exponential distribution of defect states of a-IGZO/SiO2 interface, the effects of the active layer thickness of DG a-IGZO TFTs on their elec- trical characteristics are investigated by taking into consideration the interface defect states. The results show that, as the active layer becomes thinner, the two gates of DG a-IGZO TFTs get coupled more strongly, which causes the conduction channels initially locating at the front and back interfaces of active layer to extend into the bulk of a-IG- ZO, thus greatly increasing the field effect mobility of DG a-IGZO TFTs. In addition, with the decrease of the active layer thickness, the field effect mobility of DG a-IGZO TPFs gradually becomes immune to the interface defect states, while the subthreshold swing becomes more sensitive to the interface defect states.