非晶铟镓锌氧化物薄膜晶体管(a-IGZO TFT)有望在有源矩阵有机发光显示(AMOLED)像素电路中得到实际应用, 但其电压偏置效应仍会引起电路特性的不稳定。本文利用实验室制备的a-IGZO TFT器件进行参数提取并建立了SPICE仿真模型, 通过拟合得到了它的阈值电压随时间变化的方程。在此基础上, 采用SPICE软件对基于a-IGZO TFT的2T1C和3T1C两种AMOLED 像素电路的稳定性进行了比较研究, 证明3T1C电路对阈值电压偏移确实存在一定的补偿效果。最后讨论了进一步改善AMOLED像素电路稳定特性的方法和实际效果。

Amorphous In-Ga-Zn-O thin film transistors (a-IGZO TFTs) have potentials to be used in pixel circuits of active matrix organic light emitting display (AMOLED). However, bias stress effect still involves a-IGZO TFTs, evidently influencing performance of the corresponding AMOLED pixel circuits. In this study, inverted-staggered a-IGZO TFT devices were fabricated and measured, following which the corresponding Spice model was created. In addition, the dependence of stress time on threshold voltage (Vth) shift was theoretically modeled. By using SPICE simulation tool, we studied the stability properties of a-IGZO TFT-OLED pixel circuits in the forms of 2T1C and 3T1C, which proves there exists somewhat compensation effect on the Vth shift in 3T1C pixel circuit. Finally, we discussed and analyzed the way to further improve stability of a-IGZO TFT-OLED pixel circuits.