基于二维MoS2沟道的HfO2铁电场效应晶体管辐射效应与失效机理研究

The space radiation damage of electronic devices is one of the important failure causing factors affecting the long-term reliable operation of spacecraft in orbit. With the development aerospace technology, electronic equipment on spacecraft is tend to be high performance and miniaturization, which increasing the demand for advanced radiation-hardening nanoelectronic devices. Recent studies show that two-dimensional transition-metal dichalcogenides (TMDs) have potential applications in nonvolatile data storage, the TMDs based ferroelectric field-effect transistor (FeFET) is considered as a promising candidate for future ferroelectric non-volatile memory applications. However, the ionizing radiation effects in TMDs FeFET have not been studied and reported so far. This application project is aimed at the key basic scientific problems in the ionizing radiation reliability of MoS2 FeFET, intended to investigate the ionizing radiation effect and mechanism by combining experimental analysis and theoretical modeling. It is proposed to study the ionizing radiation effect on the electrical characteristics of MoS2 FeFET during the exposure and in the post-radiated condition, reveal the varied regularity of radiation-induced degradation in the MoS2 FeFET with different device structure and radiation conditions, analyze the physical mechanism of radiation-induced damage and degradation in the MoS2 FeFET. Finally, based on the radiation experiment data, a physical model and numerical simulation will be developed to evaluate the radiation reliability and tolerance of MoS2 FeFET, which is expected to provide a scientific basis for radiation-hardened design of advanced ferroelectric memory and its future applications.

电子器件空间辐射损伤是影响航天器在轨长期可靠运行的重要因素之一，电子系统高性能及小型化的发展趋势，使空天领域对先进抗辐射纳米器件的需求日益迫切。近期二维过渡金属硫化物(TMDs)在非易失性存储方面的应用研究受到广泛关注，基于二维TMDs沟道的铁电栅场效应晶体管(TMDs FeFET)在新型铁电存储器研制领域展现出极大的潜力，然而关于TMDs FeFET辐射效应的研究目前仍无报道。本申请项目以具有代表性的二维MoS2 FeFET为研究对象，旨在揭示铁电薄膜局域电场作用下二维MoS2辐照损伤的微观演化过程，总结器件存储特性随辐照剂量的退化规律，阐明辐照条件、材料选型、工艺参数及界面效应等对器件电离辐射效应产生影响的内在机理，关联MoS2 FeFET辐照失效的关键内外部影响因素，建立MoS2 FeFET电离辐射效应物理模型，为如何评价与优化其抗辐射能力提供一定的理论基础和技术支持。

本项目按照“辐射效应-微观损伤-失效机理-物理模型”的研究思想，围绕氧化铪(HfO2)基铁电场效应晶体管(FeFET)及其存储器件电离辐射效应中的基础科学问题，从辐照实验和机理分析两方面展开研究。(1) 采用ALD方法制备了Al、Zr等元素掺杂的超薄HfO2薄膜(~10 nm)，通过调整载气、氧源、生长温度、气体流量、退火温度、薄膜厚度以及电极匹配等制备参数优化了HfO2基铁电薄膜的电学性能，探索了HfO2基铁电薄膜的生长动力学，制备了高质量的单层二维材料；(2) 采用60Co伽马源、氧等离子体等对制备的HfO2基铁电薄膜进行了电离辐照实验，使用半导体分析仪对比测试了HfO2基铁电薄膜辐照前后极化强度、矫顽场、漏电流、疲劳特性及介电常数等电学特性的变化/退化情况，利用微观表征手段(XRD、TEM、PFM、C-AFM、拉曼等)，表征了HfO2基铁电薄膜的晶体结构、表面形貌、界面缺陷和电畴翻转等特性在辐照前后变化及演变规律；(3) 制备了基于HfO2薄膜的FeFET及存储器件，对比测试了FeFET辐照前后关键电学性能的变化/退化情况，总结了其存储特性的退化规律，考虑界面缺陷、空位及辐照感生电荷等因素的综合影响，深入分析了基于HfO2薄膜的FeFET及存储器件的辐照损伤与性能退化机理并进行了TCAD模拟与仿真，提出了评价与优化HfO2基FeFET及存储器件的抗辐射能力的可行方案，为未来新型铁电存储器电离辐射效应及抗辐射加固技术的研究提供一定的理论基础和技术支持。