Unveiling the Apparent “Negative Capacitance” Effects Resulting From Pulse Measurements of Ferroelectric-Dielectric Bilayer Capacitors
Unveiling the Apparent “Negative Capacitance” Effects Resulting From Pulse Measurements of Ferroelectric-Dielectric Bilayer Capacitors
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DOI：
10.1109/led.2020.3020857
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发表时间：
2020-09
影响因子：
4.9
通讯作者：
Zhan Liu;Hao Jiang;Brandon Ordway;T. Ma
中科院分区：
文献类型：
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作者：
Zhan Liu;Hao Jiang;Brandon Ordway;T. Ma
在铁电-介电双层膜中，通过脉冲测量观察到了明显的“负电容"效应，相关结果被认为是支持准静态”负电容“（QSNC）理论的直接证据。然而，“NC”效应仅在施加足够高的电压时发生，并且甚至存在于独立的FE电容器中。这些结果与QSNC理论相矛盾，因为它预测一旦稳定（需要DE层），FE保持在“NC”状态，而不管施加的电压如何。在这封信中，通过使用成核限制开关（NLS）模型，我们提出了我们的结果，从模拟的脉冲测量的样品是类似的发表。模拟结果表明，在脉冲的下降沿发生了反向偏振开关，从而产生了明显的无色散NC效应。这项工作提供了另一种解释的实验结果，而不调用QSNC理论。
Apparent ‘Negative Capacitance’ (NC) effects have been observed in some ferroelectric-dielectric (FE-DE) bilayers by pulse measurements, and the associated results have been published that claim to be direct evidence to support the quasi-static ‘negative capacitance’ (QSNC) idea. However, the ‘NC’ effects only occur when sufficiently high voltage is applied, and even exist in stand-alone FE capacitors. These results contradict the QSNC theory, as it predicts that once stabilized (requires a DE layer), the FE remains in the ‘NC’ state regardless of the applied voltage. In this letter, by the use of Nucleation-Limited-Switching (NLS) model, we present our results obtained from simulation of pulse measurements on samples that are similar to the published ones. The simulation results indicate that reverse polarization switching occurs upon the falling edge of the pulses, which leads to the apparent hysteresis-free NC effect. This work provides an alternative interpretation of the experimental results without invoking the QSNC theory.