有源层厚度对氧化铟镓锌薄膜晶体管性能的影响

Effect of active layer thickness on the performance of IGZO thin-film-transistors

使用磁控溅射法制备了IGZO-TFT,研究有源层厚度对其电学性能的影响。实验结果表明,器件的阈值电压和开关比会随着有源层厚度的增大而减小,而器件的亚阈值摆幅和饱和迁移率则会随有源层厚度的增大而增大。此外,还研究了有源层厚度对器件偏压稳定性的影响。有源层厚度越大的器件,其阈值电压漂移也会越大。这主要与半导体层中所增加的缺陷态密度有关。

IGZO-TFTs with different active layer thicknesses were prepared using magnetron sputtering method. It isobserved that with the increasing of active layer thickness, the threshold voltage and on/off ratio decrease, while thesubthreshold swing and mobility keep an upward tendency. The variation of threshold voltage shift was studied additionally.The results indicate that the enhancement of active layer thickness has a negative impact on the device stability. It isconsidered as the consequence of growing trap state density in the semiconductor resulting from the increment of activelayer thickness.