基于铁电/介电界面电荷动力学的负电容晶体管调控机理研究

Transistor innovation based on new materials and structures towards breaking through the Boltzmann tyranny in subthreshold swing (SS) is required for beyond CMOS technologies. Negative Capacitance Field Effective Transistor (NCFET) based on ferroelectric materials is considered to be one of the most promising choices. However, the experimentally observed negative capacitance effect is quite different from the initially proposed concept. Thus, although the steep SS has been demonstrated in ferroelectric-insulator-based FET, the control of its hysteresis and range is still short of sufficient theory support and is difficult technically. Focusing on this issue, we propose that the internal potential gain, the key for getting steep SS, is closely associated with charge dynamics at ferroelectric/paraelectric interface in actual NCFET. Therefore, we are planning to experimentally and theoretically study the charge dynamics at ferroelectric/paraelectric interface and its effect on the internal potential gain, to directly and quantitatively correlate them with SS in actual NCFET, and to build up a physical and analytical model towards the control of steep SS. This study will provide significant results for deep discussion of application prospect of actual NCFET in next generation CMOS technologies, will provide theoretical support and experimental parameters for demonstrating possible high-performance-NCFET, and will bring new insights into the studying of other ferroelectric-based electron devices.

后摩尔定律时代的CMOS技术亟需可使亚阈值摆幅突破玻尔兹曼限制的新型微纳电子器件，其中基于铁电材料的负电容晶体管被认为是未来最重要的概念之一。但实验验证的负电容效应与最初概念之间具有很大不同，因而实际负电容晶体管陡峭亚阈值摆幅在区间、滞回等方面的控制依然缺乏有效的理论指导，存在很大的技术难度。针对这样的难题，本项目提出内部电压放大作为陡峭亚阈值摆幅实现的关键与铁电/介电界面电荷动力学密切相关；因此拟从理论和实验两方面系统深入地研究铁电/介电界电荷动力学及其对内部电压放大的影响，并获得它们与陡峭亚阈值摆幅之间的定量相关关系；以此为基础，建立新的面向实际负电容晶体管陡峭亚阈值摆幅控制的物理和数学模型。本项目的开展对深入探讨实际负电容晶体管在未来CMOS技术中的应用前景具有重要的意义，将为可能的高性能负电容晶体管的实现提供有效的理论指导和实验参数，也对其它新型铁电微纳电子器件的研发具有指导意义。

后摩尔定律时代的CMOS技术亟需可使亚阈值摆幅突破玻尔兹曼限制的新型微纳电子器件，其中基于铁电材料的负电容晶体管被认为是未来最重要的概念之一。但目前学术界对负电容晶体管实际工作机制存在很大的争议。针对该关键问题，本项目着眼于内部电压放大效应作为陡峭亚阈值摆幅实现的关键，实现了对铁电/介电界面电荷动力学的物理和数学建模，并在此基础上设计实验，验证了其与内部电压放大效应之间的关系，并进一步验证了内部电压放大效应和铁电晶体管陡峭亚阈值摆幅之间存在的直接关系，在此基础上建立了面向面向实际负电容晶体管陡峭亚阈值摆幅控制的物理和数学模型。