Hysteretic resistance concepts in ferroelectric thin films
Hysteretic resistance concepts in ferroelectric thin films
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DOI：
10.1063/1.2337078
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发表时间：
2006-09-01
影响因子：
3.2
通讯作者：
Waser, Rainer
中科院分区：
文献类型：
--
作者：
Meyera, Rene;Waser, Rainer
基于铁电极化和电导率之间的相关性的磁滞电阻效应可能会成为非易失性存储器应用特别感兴趣的，因为它们不受诸如铁电随机存取存储器之类的基于电荷的存储器的缩放限制。文献中讨论了两个基本概念：金属-铁电-金属结构和金属-铁电-半导体结构。本贡献根据频带模型讨论了这些概念的操作原理。提出了一种基于导电金属-铁电体-半导体-金属结构的广义模型。这里，低导电状态和高导电状态的存在源于铁电层中极化的切换以及在铁电-半导体界面处产生的正极化或负极化电荷。薄膜中的电荷载流子在界面处被吸引或耗尽，从而产生不同的局部电导率。通过仿真，估计了移动电荷载流子引起的内部屏蔽对铁电体中磁滞电流-电压行为和去极化场的影响。模拟揭示了高达几个数量级的开关比和随施主浓度变化的电导率窗口。假设存在非铁电界面层，它还可以解释仅由一个铁电层组成的系统中的电阻切换。 (c) 2006 年美国物理研究所。
Hysteretic resistance effects based on a correlation between ferroelectric polarization and conductivity might become of particular interest for nonvolatile memory applications, because they are not subject to the scaling restrictions of charge based memories such as the ferroelectric random access memory. Two basic concepts, a metal-ferroelectric-metal structure and a metal-ferroelectric-semiconductor structure are discussed in the literature. This contribution discusses the principle of operation of those concepts in terms of the band model. A generalized model is proposed, which is based on a conductive metal-ferroelectric-semiconductor-metal structure. Here, the existence of a low and a high conductive state originates from a switch of the polarization in the ferroelectric layer and a resulting positive or negative polarization charge at the ferroelectric-semiconductor interface. Charge carriers in the film are attracted by or depleted at the interface giving rise to different local conductivities. By simulation, the effect of internal screening caused by mobile charge carriers on the hysteretic current-voltage behavior and the depolarizing field in the ferroelectric are estimated. The simulation discloses a switching ratio up to several orders of magnitude and a conductivity window, which scales with the donor concentration. It may also explain resistive switching in systems consisting only of one ferroelectric layer by assuming the presence of nonferroelectric interface layers. (c) 2006 American Institute of Physics.