Effects of Moisture on the Switching Characteristics of Oxide-Based, Gapless-Type Atomic Switches
Effects of Moisture on the Switching Characteristics of Oxide-Based, Gapless-Type Atomic Switches
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DOI：
10.1002/adfm.201101846
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发表时间：
2012-01-11
影响因子：
19
通讯作者：
Aono, Masakazu
中科院分区：
文献类型：
--
作者：
Tsuruoka, Tohru;Terabe, Kazuya;Aono, Masakazu
基于在简单的金属/氧化物/金属结构中形成和溶解金属丝的电阻开关存储器是有吸引力的，因为它们潜在的高可扩展性、低功耗和易于操作。从操作机制的观点来看，这些类型的存储器器件被称为无间隙型原子开关或电化学金属化单元。众所周知，氧化物材料可以从环境空气中吸收水分，这导致金属氧化物半导体器件的特性发生变化。然而，环境湿度对基于氧化物的原子开关的操作的作用尚未被阐明。在这项工作中，电流-电压测量作为环境水蒸气压力和温度的函数进行，以揭示使用不同的氧化物材料的Cu/氧化物/Pt原子开关的开关行为上的水分的影响。主要调查结果如下：i）在阳极界面处的Cu的电离可能归因于经由氧化物层中的残余水的化学氧化，ii）Cu离子沿着氧化物层中的晶界迁移，其中氢键网络可能通过水分吸收形成，以及iii）残余水的稳定性对电离和迁移过程具有影响，并且在确定操作电压中起主要作用。这些发现将是重要的氧化物为基础的原子开关和电化学金属化电池的开关行为的微观理解。
Resistive switching memories based on the formation and dissolution of a metal filament in a simple metal/oxide/metal structure are attractive because of their potential high scalability, low-power consumption, and ease of operation. From the standpoint of the operation mechanism, these types of memory devices are referred to as gapless-type atomic switches or electrochemical metallization cells. It is well known that oxide materials can absorb moisture from the ambient air, which causes shifts in the characteristics of metal-oxide-semiconductor devices. However, the role of ambient moisture on the operation of oxide-based atomic switches has not yet been clarified. In this work, currentvoltage measurements were performed as a function of ambient water vapor pressure and temperature to reveal the effect of moisture on the switching behavior of Cu/oxide/Pt atomic switches using different oxide materials. The main findings are: i) the ionization of Cu at the anode interface is likely to be attributed to chemical oxidation via residual water in the oxide layer, ii) Cu ions migrate along grain boundaries in the oxide layer, where a hydrogen-bond network might be formed by moisture absorption, and iii) the stability of residual water has an impact on the ionization and migration processes and plays a major role in determining the operation voltages. These findings will be important in the microscopic understanding of the switching behavior of oxide-based atomic switches and electrochemical metallization cells.