讨论了基于柔性PI基底上的底栅型TFT器件工艺,通过工艺优化解决了双层结构干刻速率不同造成的下切角形状。本文TFT器件是基于氧化物IGZO为有源层,栅绝缘层采用Si3N4/SiO2双层结构,采用两次补偿曝光、干刻方式消除干刻引入的下切角形状,有效解决了薄膜沉积引入的断线风险。实验结果表明,经过SEM断面观察,干刻后双层结构taper角度适合TFT器件后续沉膜条件,柔性基底上制作的TFT器件迁移率达到14.8 cm2/(V·s),阈值电压Vth约05 V,亚域值摆幅SS约0.5 V/decade,TFT器件的开关比Ion/Ioff > 106。通过此方法制作出的器件性能良好,满足LCD、OLED或电子纸的驱动要求。

Bottom-gate structure TFT device technology on flexible PI substrate was discussed in the paper. Undercut shape of the double layer caused by the different dry etching rate was solved by the improvement of technics. The TFT device was based on IGZO as active layer,and Si3N4/SiO2 double layer structure was employed as gate insulator,undercut shape introduced thin film deposition break risk was effectively solved using two times of exposure compensation. The experimental results show that,the taper angle of double-layer structure after dry etching which was observed using SEM was suitable for following film deposition of TFT devices. The mobility of TFT on flexible PI substrate reaches 14.8 cm2/(V·s),threshold voltage of Vth is about 0.5 V,subthreshold swing (SS) is about 0.5 V/decade,and ratio of Ion/Ioff is upper 106. TFT device performance by this method is good,and meets the driving requirements of LCD,OLED or electronic paper.