金属元素与氢共掺杂下氧化锌薄膜缺陷调控研究及器件研制

Recently, based the thin film transistors (TFTs) the new flat panel display has become one of the important development direction of information industry. Znic oxide (ZnO), which is the representatives of metal oxide TFTs, has tremendous attentions due to their low cost, high optical transparency, and potential for low-temperature film processing. However, the improved performance of ZnO TFTs may meet the demands of the ultra-high-resolution, high frame rate and large panel size as a megatrend of flat panel displays. The method by metal element doping is not easily to overcome the trade-off between performance and stability in the ZnO TFTs. Hydrogen can act as shallow donors in ZnO while hydrogen could diffuse rapidly even at a moderately raised temperature. In view of the above problem, we will adopt metal element and hydrogen codoping of ZnO, and focus on the formation of defect with hydrogen after codoping. We anticipate that hydrogenation in metal oxide TFTs will become a key technology for next-generation displays with high mobility and high stability.

近年来，以薄膜晶体管为开关或驱动元件的平板显示技术已经成为信息产业的重要发展方向之一。以氧化锌为代表的金属氧化物薄膜晶体管因为低成本、高透明、可低温制备等优点受到广泛关注。但氧化锌薄膜晶体管的性能有待提升才能满足未来高分辨率、高帧率、大尺寸平板显示器的要求。常用的金属元素掺杂的氧化锌薄膜晶体管很难克服器件性能和稳定性平衡的制约；虽有研究表明氢在氧化锌中起浅施主作用，但却表现出易扩散不稳定。本项目拟采取金属元素和氢共掺技术，着重研究共掺后氢在氧化锌的各种缺陷的形成，阐明阻碍氢在氧化锌中浅施主作用和钝化缺陷作用的内在机理，期望能获得非补偿性的共掺，提高载流子浓度，钝化缺陷，实现电学性能调控的高性能薄膜晶体管。

由于显示市场对高分辨、高帧率、大尺寸显示的巨大需求，非晶硅、低温多晶硅薄膜晶体管技术难以满足技术要求，金属氧化物薄膜晶体管因为其低成本、高迁移率、高透明、可低温制备等优点成为下一代显示技术的核心要素。本项目主要围绕氧化锌基金属氧化物中氧空位缺陷的调控来提升性能，充分认识了氧空位缺陷对材料电学性能的作用机理，揭示了在氧化锌中氢掺杂的氢隐藏问题的机理。在提升器件性能和稳定性平衡方面，我们采用两种方案来解决，一种是共掺的方法，例如Mg和H共掺，N和H共掺的方法都很好的实现了性能和稳定性都得到提升；另外一种是用双沟道有源层来调控界面处的界面态，充分发挥氢在氧化锌基材料中的两种积极作用，充当浅施主和钝化缺陷的作用，实现了器件电学性能和稳定性的明显提升，例如在Mg和H共掺的氧化锌薄膜晶体管中，迁移率从10提升至32.4 cm2/VS，热稳定性和偏压稳定性得到显著提升；在插入薄层掺氢的氧化锌同质沟道薄膜晶体管中，迁移率从10提升至42.6 cm2/VS，正负偏压稳定性得到明显提升。项目取得成果充分证明金属和氢共掺技术可以有效的固定氢，发挥氢的双重作用，氢掺杂技术推广到氧化物半导体材料中是行之有效的。