Effects of Gate Stack Composition and Thickness in 2-D Negative Capacitance FETs
Effects of Gate Stack Composition and Thickness in 2-D Negative Capacitance FETs
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DOI：
10.1109/jeds.2019.2922441
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发表时间：
2019-06
影响因子：
2.3
通讯作者：
Yuh-Chen Lin;Felicia A. McGuire;Steven G. Noyce;Nicholas X. Williams;Zhihui Cheng;J. Andrews;A. Franklin
中科院分区：
文献类型：
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作者：
Yuh-Chen Lin;Felicia A. McGuire;Steven G. Noyce;Nicholas X. Williams;Zhihui Cheng;J. Andrews;A. Franklin
具有二维半导体通道的负电容场效应晶体管（fet）由于能够在物理可扩展器件中产生低于60 mV/dec的开关行为而变得越来越有吸引力。然而，还没有确定栅极控制，包括阈值电压，是如何受到栅极介电成分，以及介电层和铁电层厚度的影响的。在这里，我们显示阈值电压随铁电厚度的增加而正移，随介电厚度的增加而负移。在铁电氧化铪锆（HfZrO2或HZO）和电介质之间没有界面金属层的器件中观察到这种移位行为。由于铁电介质和介电介质之间的界面是驱动NC行为的关键，我们还研究了4 nm HZO与不同介电介质配对的二维NC- fet。这些结果表明，HZO/Al2O3界面比HZO/ZrO2或HZO/HfO2界面更有利。最后，通过比较有金属界面层和没有金属界面层的类似器件的二维NC-FET性能，讨论了金属界面层的影响。
Negative capacitance (NC) field-effect transistors (FETs) with 2-D semiconducting channels have become increasingly attractive due to their ability to produce sub-60 mV/dec switching behavior in a physically scalable device. However, it has yet to be determined how gate control, including threshold voltage, of 2-D NC-FETs is impacted by gate dielectric composition, along with dielectric and ferroelectric layer thicknesses. Here, we show the threshold voltage shifts positively under increasing ferroelectric thickness and negatively with increasing dielectric thickness. This shifting behavior is observed in devices without an interfacial metal layer between the ferroelectric hafnium zirconium oxide (HfZrO2 or HZO) and dielectric. Because the interface between the ferroelectric and dielectric is critical in driving NC behavior, we also study 2-D NC-FETs with 4 nm HZO paired with different dielectrics. These results reveal that the HZO/Al2O3 interface is more favorable than either the HZO/ZrO2 or HZO/HfO2 interfaces. Finally, the impact of an interfacial metal layer is discussed by comparing the 2-D NC-FET performance of similar devices with and without this layer.