双电层氧化锌薄膜晶体管偏压应力稳定性

Bias Stress Stability of Electric-double-layer ZnO Thin-film Transistor

以环保可降解的天然生物材料制备功能器件越来越受到关注,利用天然鸡蛋清作为栅介质层,采用射频磁控溅射法在其上沉积ZnO薄膜有源层,制备低压双电层氧化锌基薄膜晶体管(ZnO-TFT)并对其电学特性进行了表征,研究了器件在栅偏压和漏偏压应力下电性能的稳定性及其内在的物理机制。该ZnO-TFT器件呈现出良好的电特性,载流子饱和迁移率为5.99 cm^(2)/(V·s),阈值电压为2.18 V,亚阈值摆幅为0.57 V/dec,开关电流比为1.2×10^(5),工作电压低至3 V。研究表明,在偏压应力作用下,该ZnO-TFT器件电性能存在一定的不稳定性,我们认为栅偏压应力引起的电性能变化可能来源于栅介质附近及界面处的正电荷聚集、充放电效应和新陷阱态的复合效应;漏偏压应力引起的电性能变化可能来源于焦耳热引起的氧空位及沟道中的电子陷阱。

The use of environmentally friendly and degradable natural biomaterials to make functional devices has attracted more and more attention.Low-operating-voltage electric-double-layer(EDL)ZnO thin-film transistor(ZnO-TFT)was prepared by radio frequency magnetron sputtering by using natural albumen as a gate dielectric layer and ZnO as an active layer.The electrical characteristics of EDL ZnO-TFT was characterized,and the stability and its physical mechanism of the device under gate-bias and drain-bias stresses were investigated.The ZnO-TFT shows good electrical properties with a saturation mobility of 5.99 cm^(2)/(V·s),a threshold voltage of 2.18 V,a subthreshold swing of 0.57 V/dec,an on/off current ratio of 1.2×10^(5),and an operating voltage of less than 3 V.Bias-stress stability analysis indicated that the electrical properties of the ZnO-TFT have obvious instability under the gate and drain bias stresses.We believe that the change of electrical properties caused by gate bias stress may come from the positive charge accumulation near the gate dielectric and the interface,the charge discharge effect and the composite effect of new trap states;the change of electrical properties caused by drain bias stress may come from the oxygen vacancy caused by Joule heat and the electron trap in the channel.