Gao Shuang, Zeng Fei, Wang Minjuan, Wang Guangyue, Song Cheng, Pan Feng
Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084, People's Republic of China.
Phys Chem Chem Phys. 2015 May 21;17(19):12849-56. doi: 10.1039/c5cp01235j.
The common nonpolar switching behavior of binary oxide-based resistive random access memory devices (RRAMs) has several drawbacks in future application, such as the requirements for a high forming voltage, a large reset current, and an additional access device to settle the sneak-path issue. Herein, we propose the tuning of the switching behavior of binary oxide-based RRAMs by inserting an ultra-thin chemically active metal nanolayer, and a case study on Ta2O5-Ta systems is provided. The devices are designed to be Pt/Ta2O5(5 - x/2)/Ta(x)/Ta2O5(5 - x/2)/Pt with x = 0, 2, or 4 nm. The reference devices without the Ta nanolayer exhibit an expected nonpolar switching behavior with a high forming voltage of ∼-4.5 V and a large reset current of >10 mA. In contrast, a self-compliance bipolar switching behavior with a low forming voltage of ∼-2 V and a small reset current of <1 mA is observed after inserting a 2 nm Ta nanolayer. When the Ta nanolayer is increased to 4 nm, a complementary resistive switching (CRS) behavior is found, which can effectively settle the sneak-path issue. The appearance of CRS behavior suggests that a thin Ta nanolayer of 4 nm is robust enough to act as an inner electrode. Besides, the behind switching mechanisms are thoroughly discussed with the help of a transmission electron microscope and temperature-dependent electrical measurements. All these results demonstrate the feasibility of tuning switching behavior of binary oxide-based RRAMs by inserting an ultra-thin chemically active metal nanolayer and might help to advance the commercialization of binary oxide-based RRAMs.
基于二元氧化物的电阻式随机存取存储器（RRAM）常见的非极性开关行为在未来应用中存在几个缺点，例如需要高形成电压、大复位电流以及额外的访问器件来解决潜行路径问题。在此，我们提出通过插入超薄化学活性金属纳米层来调整基于二元氧化物的RRAM的开关行为，并提供了关于Ta2O5-Ta系统的案例研究。这些器件设计为Pt/Ta2O5(5 - x/2)/Ta(x)/Ta2O5(5 - x/2)/Pt，其中x = 0、2或4 nm。没有Ta纳米层的参考器件表现出预期的非极性开关行为，形成电压约为-4.5 V，复位电流大于10 mA。相比之下，插入2 nm Ta纳米层后观察到自顺应双极开关行为，形成电压约为-2 V，复位电流小于1 mA。当Ta纳米层增加到4 nm时，发现了互补电阻开关（CRS）行为，这可以有效解决潜行路径问题。CRS行为的出现表明4 nm的薄Ta纳米层足够坚固，可以用作内部电极。此外，借助透射电子显微镜和温度相关的电学测量对背后的开关机制进行了深入讨论。所有这些结果证明了通过插入超薄化学活性金属纳米层来调整基于二元氧化物的RRAM开关行为的可行性，并可能有助于推动基于二元氧化物的RRAM的商业化。
