Dias Catarina, Guerra Luís M, Bordalo Bernardo D, Lv Hua, Ferraria Ana M, Botelho do Rego Ana M, Cardoso Susana, Freitas Paulo P, Ventura João
IFIMUP-IN and Department of Physics and Astronomy, Faculty of Sciences, Porto, Portugal.
Phys Chem Chem Phys. 2017 May 3;19(17):10898-10904. doi: 10.1039/c7cp00062f.
Resistive switching in metal-insulator-metal nanosctructures is being intensively studied for nonvolatile memory applications. Here, we report unipolar resistive switching in Pt/MgO/Ta/Ru structures, with a 30 nm oxide barrier. A forming process was needed to initiate the resistive switching, which was then observed for all Set and Reset voltage polarity combinations. We studied the influence of the voltage polarity on the variability of the Set/Reset voltages and ON/OFF resistances and revealed the importance of a thin TaO layer working as an oxygen revervoir for resistive switching. The mechanism behind this phenomenon can be understood in terms of conductive filaments formation/rupture with a contribution from Joule heating. Resistance change is thus caused by a voltage-driven oxygen vacancy motion in the MgO layer and a filament model was proposed for each polarity mode. A OFF/ON resistance ratio of at least 2 orders of magnitude was obtained with resistive states stable up to 10 s. Our results open the prospect to improve switching performance in other resistive switching systems, by proving a better understanding of the differences between operation modes.
金属-绝缘体-金属纳米结构中的电阻开关因其在非易失性存储器中的应用而受到广泛研究。在此，我们报道了具有30nm氧化物势垒的Pt/MgO/Ta/Ru结构中的单极电阻开关。需要一个形成过程来启动电阻开关，随后在所有设置和重置电压极性组合中均观察到该现象。我们研究了电压极性对设置/重置电压和开/关电阻变化的影响，并揭示了作为电阻开关氧储存器的薄TaO层的重要性。这种现象背后的机制可以通过焦耳热导致的导电细丝形成/破裂来理解。因此，电阻变化是由MgO层中电压驱动的氧空位运动引起的，并针对每种极性模式提出了细丝模型。在电阻状态稳定长达10秒的情况下，获得了至少2个数量级的关/开电阻比。我们的结果通过更好地理解操作模式之间的差异，为改善其他电阻开关系统的开关性能开辟了前景。
