高可靠性InGaZnO薄膜晶体管集成栅极驱动电路的研究  

Study of Highly Reliable Gate Driver on Array Based on InGaZnO Thin Film Transistor

作　　者：周刘飞 邵贤杰 陈旭 王海宏 王保平[1] ZHOU Liu-fei;SHAO Xian-jie;CHEN Xu;WANG Hai-hong;WANG Bao-ping(School of Electronic Science and Engineering,Southeast University,Nanjing,Jiangsu 210096,China;Research and Development Department,Nanjing BOE Display Technology Co.,Ltd.,Nanjing,Jiangsu 210033,China)

机构地区：[1]东南大学电子科学与工程学院,江苏南京210096 [2]南京京东方显示技术有限公司研发部,江苏南京210033

出　　处：《电子学报》2022年第12期3014-3020,共7页Acta Electronica Sinica

摘　　要：InGaZnO薄膜晶体管(InGaZnO Thin Film Transistor,IGZO TFT)具有高迁移率特性,易实现高分辨率且高刷新率的有源矩阵液晶显示(Liquid Crystal Displays,LCD).然而,由于IGZO TFT长期运行后较严重的性能下降,集成栅极驱动电路(Gate Driver on Array,GOA)的使用寿命受到限制,这成为IGZO GOA在大尺寸LCD应用的一个关键障碍.本文提出一种具有双维持模块的高可靠性IGZO GOA电路,适用于大尺寸高分辨率LCD,其中维持电路产生的双极性脉冲偏压可以有效抑制IGZO TFT阈值电压(Threshold Voltage,V_(TH))漂移.详细分析了该GOA电路的工作原理,并进行了相关电学模拟.再者,表征了偏压温度应力下的TFT稳定性,以证明双极性脉冲偏压抑制V_(TH)漂移的有效性.采用本文提出的新型GOA电路,制作了55英寸UHD(3840×2160)高分辨率LCD,具有5 mm窄边框特征,其中GOA电路仅占用1.47 mm.此外,信赖性测试中,该GOA电路在高温高湿(60°C/90%)环境稳定工作1000小时.这些结果表明本文提出的IGZO GOA电路应用于大尺寸高分辨率LCD具有足够的可靠性.Due to the high mobility of InGaZnO thin-film transistor(IGZO TFT),the active matrix liquid crystal dis⁃play(LCD)using IGZO TFT is able to provide high resolution and high frame frequency.However,the lifetime of IGZO gate driver on array(GOA)is limited since the IGZO TFT usually suffers severe performance degradation after a long time operation,which comes to be a critical obstacle for GOA's application in large-sized LCDs.In this paper,a highly reliable IGZO GOA circuit with a dual low-level holding structure is proposed and fabricated for large-sized and high resolution LCD applications,in which bipolar pulse bias(BPB)is generated to suppress the threshold voltage(V_(TH))shift of IGZO TFT.The proposed GOA circuit can be divided into several units for different functions:pull-up control unit,pull up unit,pull down unit,low-level holding unit,and reset unit.The operation principle of the GOA is described in detail,and the related simulation is conducted.Then,bias temperature stress(BTS)measurements are performed to demonstrate the effectiveness of the BPB in suppressing the V_(TH)shift.With this GOA,a 55-inch UHD(3840×2160)high resolution LCD panel with a 5 mm narrow bezel is achieved,in which the layout dimension of GOA circuit is only 1.47 mm.In addition,in a reliability test,the new GOA circuit operates stably at high temperature and high humidity(60°C/90%)for 1000 h.These results can well prove that designed GOA has good enough reliability for large-sized and high resolution LCD.

关 键 词：InGaZnO薄膜晶体管 集成栅极驱动 阈值电压漂移 双极性脉冲偏压 可靠性 拉伸-指数方程 

分 类 号：TN321.5[电子电信—物理电子学]