柔性显示用金属氧化物薄膜晶体管电极材料的设计与研制

Metal oxide semiconductor (MOS) thin film transistor (TFT) is considered to be one of the most suitable device to fabricate high performance flexible display because of their advantages in high carrier mobility, good uniformity, low cost and low process temperature. MOS-TFT has attracted much attention of the scientists and industrial circles. The high performance electrode is the key technology to realize the low power consumption, ultra-high resolution and high reliability application in flexible display, but the core problem influenced on the research of flexible electrode material does not make breaking through so far. In this project, a novel Cu alloy electrode material was proposed to study the effect of doping elements on electrode performance, including element selection, component optimization, thin film deposition, patterning and post-treatment techniques. Combined with MOS-TFT device structure, preparation process and layout design studies of the flexible substrate, we can build physical models to guide material design and device preparation. By studying the mechanism of Cu alloying, we hope to grasp the key technology of Cu alloy low-temperature post-treatment suitable for flexible substrate. By investigating the basic scientific problems of interfacial contact between Cu alloy electrode and MOS, insulator, passivation, and substrate, we hope to extract the general technologies of flexible high-performance electrode development and fabrication. Finally, we will fabricate flexible display devices with MOS-TFT array backplane successfully.

基于金属氧化物半导体(MOS)的薄膜晶体管(TFT)具有迁移率高、均匀性好、成本低和工艺温度低等优势，非常适合制备高性能柔性显示器件，是当前学术界和工业界研究的热点。高性能电极是实现柔性显示低功耗、超高清和高可靠应用的关键之一，但柔性电极材料的研究一直没有取得实质性突破。本课题拟开发新型Cu合金电极材料，研究掺杂元素对电极性能的影响，包括元素选择、成分优化、薄膜沉积、图形化和后处理技术等，并结合柔性基板MOS-TFT器件结构、界面物理、制备工艺和版图设计的研究，建立物理模型，深层次指导材料设计和器件制备。通过研究Cu电极合金元素掺杂的机理，掌握适用于柔性基板的Cu合金低温后处理关键技术；通过研究电极与MOS等材料界面接触特性的基本科学问题，凝练出柔性高性能电极的开发和制备方法，实现其在MOS-TFT阵列背板柔性显示器件中的应用。

铜电极在金属氧化物TFT器件中有着广泛的应用前景，本项目采用微量多元的思路通过Cr和Zr等元素掺杂获得具有高导电性和高粘附性的CuCrZr(CCZ)电极材料。在研究中，首先结合金属导电机理以及铜的物理化学性质，选择了Cr和Zr两种掺杂元素，并分别探究对于铜合金电极的影响机理。通过研究确定了CCZ优化组分的范围后，对其成膜工艺进行探索，包括磁控溅射、化学蚀刻和低温退火等，获得了CCZ合金从靶材到图形化电极的全链条技术。CCZ薄膜不仅结合强度高达4B-5B，而且电阻率可接近纯铜材料，有效地解决了常规合金电极面临的高结合强度和高导电性难以兼得的矛盾。PI基板的铜合金(CCZ)栅极柔性NdIZO-TFT器件，其饱和迁移率(μsat)达27.1cm2·V-1·s-1，开关比(Ion/Ioff)达2.87×10E7，亚阈值摆幅(SS)为0.28V/decade，阈值电压(Vth)为0.09V；经过1万次1mm曲率半径的弯折,Vth仅漂移0.19V，μsat变化率仅为0.37%。全铜合金(CCZ)电极柔性NdIZO-TFT器件，μsat达32.1cm2·V-1·s-1，Ion/Ioff达4.10×10E7，SS为0.16V/decade，Vth为0.42V。铜合金(CCZ)电极TFT表现出了较好电学稳定和抗弯折特性：Vth漂移为-0.28V(偏压时间5400s@±1MV/cm)，Vth漂移为-0.32V(静态曲率半径2.5mm)，Vth为漂移-0.29V(动态曲率半径4mm@1万次)。本研究为高性能柔性显示的超高清和高刷新器件进一步发展提供了材料基础，填补了目前关于低温后处理铜合金柔性电极材料的空白，也为后续可穿戴电子用高结合强度和高导铜电极的开发提供借鉴。项目期间共资助发表SCI论文12篇，专利6篇。培养博士生5名，硕士生2名。项目投入经费60万元，支出57.4636万元，各项支出与预算相符。