School of Liberal Arts, Korea University of Technology and Education, Cheonan 31253, Republic of Korea.
Nanoscale. 2018 Jul 19;10(28):13443-13448. doi: 10.1039/c8nr02986e.
We report the effects of bottom electrode shapes on resistive random-access memory (RRAM) devices composed of Nb (bottom electrode)/NiO (dielectric)/Nb (top electrode) structures. By adopting a nano-fabrication process using an anodic aluminum oxide (AAO) nanotemplate, a well-aligned Nb nanopin array bottom electrode was formed on the surface of a Si substrate. For comparison, a Nb thin film was employed as a different type of bottom electrode. Then, a NiO thin film dielectric was prepared on both the Nb bottom electrodes via a spin coating method, followed by Nb sputtering for the Nb top electrode. Both the RRAM devices with Nb nanopin and thin film bottom electrodes exhibited typical unipolar resistive switching behavior. However, a lower SET/RESET voltage was observed for the Nb nanopin electrode compared to the Nb thin film electrode by virtue of an enhanced electric field induced by the nanopin-shaped electrode. More significantly, on the basis of endurance and retention characteristics, the Nb nanopin electrode played a key role in minimizing the dispersion of the low- and high-resistance state currents and the variation in the SET/RESET voltage by developing more-concise conducting filaments in the conducting path. Therefore, we foresee that this approach can provide an insight into the optimal design of RRAM devices.
我们报告了底部电极形状对由 Nb（底部电极）/NiO（介电层）/Nb（顶部电极）结构组成的电阻式随机存取存储器（RRAM）器件的影响。通过采用使用阳极氧化铝（AAO）纳米模板的纳米制造工艺，在 Si 衬底表面形成了排列良好的 Nb 纳米销阵列底部电极。为了进行比较，使用了 Nb 薄膜作为另一种类型的底部电极。然后，通过旋涂法在两个 Nb 底部电极上制备了 NiO 薄膜介电层，然后通过溅射 Nb 制备了 Nb 顶部电极。具有 Nb 纳米销和薄膜底部电极的 RRAM 器件均表现出典型的单极电阻开关行为。然而，由于纳米销形电极增强的电场，与 Nb 薄膜电极相比，Nb 纳米销电极的 SET/RESET 电压更低。更重要的是，基于耐久性和保持特性，Nb 纳米销电极通过在导电路径中形成更简洁的导电丝，在最小化低电阻状态和高电阻状态电流的分散以及 SET/RESET 电压的变化方面发挥了关键作用。因此，我们预计这种方法可以为 RRAM 器件的优化设计提供思路。
