Analytical calculations corroborated by the finite element modeling show that thin films of Van der Waals ferrielectrics covered by a 2D‐semiconductor are promising candidates for the controllable reduction of the dielectric layer capacitance due to the negative capacitance (NC) effect emerging in the thin films. The NC state is conditioned by energy‐degenerated poly‐domain states of the ferrielectric polarization induced in the films under incomplete screening conditions in the presence of a dielectric layer. Calculations performed for the FET‐type heterostructure “ferrielectric CuInP2S6 film—2D‐MoS2 single‐layer—SiO2 dielectric layer” reveal the pronounced size effect of the multilayer capacitance. Derived analytical expressions for the electric polarization and multilayer capacitance allow to predict the thickness range of the dielectric layer and ferrielectric film for which the NC effect is the most pronounced in various Van der Waals ferrielectrics, and the corresponding subthreshold swing becomes much less than the Boltzmann's limit. Obtained results can be useful for the size and temperature control of the NC effect in the steep‐slope ferrielectric FETs.

中文翻译：

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范德华铁电场效应晶体管中负电容状态和亚阈值摆幅的尺寸效应


有限元建模证实的分析计算表明，由于薄膜中出现负电容 （NC） 效应，由 2D 半导体覆盖的范德华铁电薄膜是可控降低介电层电容的有希望的候选者。NC 状态受在介电层存在下不完全筛选条件下薄膜中诱导的铁电极化的能量简并多域状态的条件。对 FET 型异质结构“铁电 CuInP2S6 薄膜—2D-MoS2 单层—SiO2 介电层”进行的计算揭示了多层电容的显着尺寸效应。通过推导出电极化和多层电容的解析表达式，可以预测介电层和铁电薄膜的厚度范围，其中 NC 效应在各种范德华铁电介质中最为明显，相应的亚阈值摆幅远小于玻尔兹曼极限。获得的结果可用于控制陡峭斜率铁电 FET 中 NC 效应的大小和温度。