同元界面修饰WSnZnO薄膜晶体管及其稳定性研究

With its low cost, simple technology and being free of vacuum system, solution-process has become one of fabrication technologies for oxide thin film transistors in the future. It is of far-reaching significance to promote practical application and industrialization to manufacture the environment-friendly (indium-free) TFTs with low power consumption ( high-k insulator ) by solution technique. .Taking the indium-free WSnZnO as active layer, this project uses WO3 as interface modification layer to fabricate TFTs by solution method. WO3 has the same element W with WZnSnO films which may be useful to decrease defect atoms and carrier scattering center of interface element diffusion into active layer. In this project, the WSnZnO films will be prepared by steam-aided combustion technology, the role of high valence W will be deeply investigated, and the mechanism of suppression O-H bond in WSnZnO films will be explained and revealed systematically. Meanwhile, composite material with the properties of high-k and high-Eg will be designed and utilized as the gate insulator TFT. .This project mainly studies the influence of interface modification layer WO3 on the device performance. The effect of preparing process of WO3 on W diffusion in WSnZnO films will be studied by SIMS, XPS and C-V measurement. The relation between W distribution and interface defect state will be established. TFT device with excellent property can be prepared by the optimal process condition. Stability mechanism of TFT devices under the voltage bias, illumination and temperature stress will be discussed and revealed by C-V testing and in-situ Hall measurement. .The implementation of this project is not only helpful to discover the relative theory of TFT prepared by solution method, but also contribute to the practical application.

溶液法由于其制造成本低，技术简单，无需真空设备等优点，已成为未来制造氧化物薄膜晶体管（TFT）的新型技术之一。因而研究溶液法制备具有环境友善（无铟）有源层的TFT，对于推动其实用化及产业化具有深远的意义。本项目采用溶液法制备WO3作为栅绝缘层/有源层界面修饰层（同元界面修饰，与有源层WSnZnO具有相同的元素）的WSnZnO氧化物 TFT。在溶液法烧结成膜中引入水蒸气辅助成膜降低薄膜的缺陷，研究高价态W在WSnZnO薄膜中的作用，制备功能梯度栅极绝缘层薄膜材料。研究同元界面修饰层WO3中W在WSnZnO的扩散分布规律，建立W分布与界面缺陷的关系，从而制备性能良好的氧化物TFT。通过C-V测试及原位Hall测试分析器件在偏压、辐照以及热场长时间应力作用下体缺陷态及界面缺陷态演变规律，从而揭示器件的稳定性机制。本项目的实施，不仅利于突破溶液法氧化物TFT的理论，也将为其实用化奠定基础。

溶液法由于其制造成本低、技术简单、无需真空设备优点，已成为未来制造氧化物薄膜晶体管的新型技术之一。项目基于溶液法自主设计了一种高效水蒸气氧化退火新系统，通过开发快速高效的前驱体溶液制备新技术，发明了一种High-k材料制备新方法，并探索了一种非晶绝缘层界面修饰新材料，研制了一种低温快速激光退火的烧结新工艺。制备了无铟有源层WZTO薄膜及界面修饰方法，揭示了界面修饰层对界面缺陷的控制及稳定性影响规律，实现了稳定WZTO TFT器件的制备，构建了声化学法制备WZTO TFT的理论体系。开发了双沟道层TFT的界面缺陷调控方法，探讨了W的掺杂作用以及WZTO TFT的导电机理，分析了界面修饰层对绝缘层薄膜界面缺陷调控机制。并研究了界面修饰层对器件性能的影响，器件迁移率从3.08 cm2V-1s-1增加至5.90 cm2V-1s-1。通过水蒸气辅助烧结的来调节器件性能，迁移率可达6.51 cm2V-1s-1、电流开关比可达2.7×108。同时，开发了可替代传统前驱体水浴加热法制备的快速溶液制备法，溶液制备效率提高了1800%倍。研究了一种激光扫描退火烧结新工艺，实现了TFT器件的低温快速制造，有效解决了固溶处理的金属氧化物半导体与聚合物衬底之间的不兼容问题。本项目的实施，不仅有利于理解溶液法氧化物TFT的相关机理，而且也为其实用化奠定了应用基础。