Time-Dependent Negative Capacitance Effects in Al2O3/BaTiO3 Bilayers

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• 作者：Yu Jin Kim ; Hiroyuki Yamada ; Taehwan Moon ; Young Jae Kwon ; Cheol Hyun An ; Han Joon Kim ; Keum Do Kim ; Young Hwan Lee ; Seung Dam Hyun ; Min Hyuk Park ; Cheol Seong Hwang
• 刊名：Nano Letters
• 出版年：2016
• 出版时间：July 13, 2016
• 年：2016
• 卷：16
• 期：7
• 页码：4375-4381
• 全文大小：429K
• 年卷期：0
• ISSN：1530-6992

文摘

The negative capacitance (NC) effects in ferroelectric materials have emerged as the possible solution to low-power transistor devices and high-charge-density capacitors. Although the steep switching characteristic (subthreshold swing < sub-60 mV/dec) has been demonstrated in various devices combining the conventional transistors with ferroelectric gates, the actual applications of the NC effects are still some way off owing to the inherent hysteresis problem. This work reinterpreted the hysteretic properties of the NC effects within the time domain and demonstrated that capacitance (charge) boosting could be achieved without the hysteresis from the Al₂O₃/BaTiO₃ bilayer capacitors through short-pulse charging. This work revealed that the hysteresis phenomenon in NC devices originated from the dielectric leakage of the dielectric layer. The suppression of charge injection via the dielectric leakage, which usually takes time, inhibits complete ferroelectric polarization switching during a short pulse time. It was demonstrated that a nonhysteretic NC effect can be achieved only within certain limited time and voltage ranges, but that these are sufficient for critical device applications.