非晶铟镓锌氧薄膜晶体管银/钛源漏电极的研究

Ag/Ti source/drain electrodes for amorphous InGaZnO thin flim transistors

为了适应大尺寸高分辨率显示的技术需求,研究并开发用于非晶铟镓锌氧(a-IGZO)薄膜晶体管(TFT)阵列的低电阻电极非常关键。本文采用磁控溅射制备的金属银为源漏电极,设计并制作了底栅结构的a-IGZO TFT器件。实验发现,具有单层银源漏电极的器件电学特性较差,这是因为银与a-IGZO之间不能形成良好的欧姆接触。另一方面,通过增加钛中间层而形成的Ag/Ti电极在保持低电阻的同时能够有效阻止银原子扩散并与a-IGZO形成较好的接触状态。最终制备的以Ag/Ti为源漏电极的a-IGZO TFT具有明显改善的电学特性,场效应迁移率为1.73cm^2/V·s,亚阈值摆幅2.8V/(°),开关比为2×10~7,由此证明了磁控溅射制备的银电极具有应用于非晶氧化物薄膜晶体管的实际潜力。

With the increasing requirements from large-size and high-resolution flat panel displays（FPDs）,it is necessary to investigate and develop the low-resistance electrodes for amorphous InGaZnO（a-IGZO）thin film transistors（TFTs）.In this study,the inverted staggered a-IGZO TFTs using Ag as source/drain（S/D）electrodes were designed and fabricated by magnetron sputtering.It was found that the a-IGZO TFTs with single-layer Ag S/D electrodes exhibited poor performance due to the bad contact between Ag and a-IGZO.On the other hand,the Ag/Ti electrodes,formed by inserting a Ti film between Ag and a-IGZO,could effectively prevent Ag diffusion and form good contact with the active layers.In fact,the a-IGZO TFTs with Ag/Ti electrodes showed much better performance（field effect mobility of 1.73cm^2/V·s,subthreshold swing of 2.8V/（°）,and on-off current ratio of 2×10^7）than those of the a-IGZO TFTs with single-layer Ag source/drain electrodes,proving that Ag electrodes could be potentially used in amorphous oxide TFTs.