A Study on Solution-Processed Y 2 O 3 Films Modified by Atomic Layer Deposition Al 2 O 3 as Dielectrics in ZnO Thin Film Transistor.

In this work, Y₂O₃–Al₂O₃ dielectrics were prepared and used in ZnO thin film transistor as gate insulators. The Y₂O₃ film prepared by the sol–gel method has many surface defects, resulting in a high density of interface states with the active layer in TFT, which then leads to poor stability of the devices. We modified it by atomic layer deposition (ALD) technology that deposited a thin Al₂O₃ film on the surface of a Y₂O₃ dielectric layer, and finally fabricated a TFT device with ZnO as the active layer by ALD. The electrical performance and bias stability of the ZnO TFT with a Y₂O₃–Al₂O₃ laminated dielectric layer were greatly improved, the subthreshold swing was reduced from 147 to 88 mV/decade, the on/off-state current ratio was increased from 4.24 × 10⁶ to 4.16 × 10⁸, and the threshold voltage shift was reduced from 1.4 to 0.7 V after a 5-V gate was is applied for 800 s. [ABSTRACT FROM AUTHOR]