Abstract A high-performance flexible HfO2 resistive random access memory (RRAM) device is fabricated herein on a polyimide (PI) substrate, and the effect of different top electrodes (TE) on RRAM characteristics were investigated with the same TiN bottom electrode. Compared with Al or Ni TEs, the switching characteristics of devices with indium tin oxide (ITO) TEs are improved, producing a low power consumption (50 µA@0.5 V for SET and 15 µA@-0.2 V for RESET) and high DC endurance cycles (>3 × 105). The flexible devices show stable resistive properties under different bending radii of up to 4 mm, and over 1.5 × 105 writing/erasing cycles are confirmed after bending the device 1,000 times. The switching mechanism based on ITO/HfO2 interfacial reactions is constructed, and the microscopic oxygen vacancies distribution under directional external biases is elaborated according to the C-V test under various frequencies, HRTEM and XPS data. Furthermore, it is revealed that the interface layer between the TE and the switching layer is the key role, which can maintain switching behaviors and improve electronic properties with the presence of a mechanical stress because of the stable interfacial reactions caused by Sn4+ in ITO film.

中文翻译：

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深入了解灵活 HfO2 RRAM 的界面行为和微观开关机制

摘要 本文在聚酰亚胺 (PI) 衬底上制造了一种高性能柔性 HfO2 电阻式随机存取存储器 (RRAM) 器件，并使用相同的 TiN 底部电极研究了不同顶部电极 (TE) 对 RRAM 特性的影响。与 Al 或 Ni TE 相比，采用氧化铟锡 (ITO) TE 的器件的开关特性得到改善，产生低功耗（SET 为 50 µA@0.5 V，RESET 为 15 µA@-0.2 V）和高直流耐受性循环 (>3 × 105)。柔性器件在高达 4 mm 的不同弯曲半径下显示出稳定的电阻特性，并且在弯曲器件 1,000 次后确认了超过 1.5 × 105 的写入/擦除循环。构建了基于ITO/HfO2界面反应的切换机制，根据不同频率下的CV测试、HRTEM和XPS数据详细阐述了定向外部偏置下的微观氧空位分布。此外，还揭示了 TE 和开关层之间的界面层是关键作用，它可以在机械应力的存在下保持开关行为并改善电子性能，因为 ITO 薄膜中的 Sn4+ 引起了稳定的界面反应。