Nano Group, Southampton Nanofabrication Centre, Department of Electronics and Computer Science, University of Southampton , Southampton SO17 1BJ, United Kingdom.
FEI Company , P.O. Box 80066, 5600 KA Eindhoven, The Netherlands.
ACS Appl Mater Interfaces. 2016 Aug 3;8(30):19605-11. doi: 10.1021/acsami.6b04919. Epub 2016 Jul 22.
The next generation of nonvolatile memory storage may well be based on resistive switching in metal oxides. TiO2 as transition metal oxide has been widely used as active layer for the fabrication of a variety of multistate memory nanostructure devices. However, progress in their technological development has been inhibited by the lack of a thorough understanding of the underlying switching mechanisms. Here, we employed high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) combined with two-dimensional energy dispersive X-ray spectroscopy (2D EDX) to provide a novel, nanoscale view of the mechanisms involved. Our results suggest that the switching mechanism involves redistribution of both Ti and O ions within the active layer combined with an overall loss of oxygen that effectively render conductive filaments. Our study shows evidence of titanium movement in a 10 nm TiO2 thin-film through direct EDX mapping that provides a viable starting point for the improvement of the robustness and lifetime of TiO2-based resistive random access memory (RRAM).
下一代非易失性存储很可能基于金属氧化物中的电阻开关。TiO2 作为过渡金属氧化物，已被广泛用作各种多状态存储纳米结构器件的活性层。然而，由于对底层开关机制缺乏透彻的了解，它们的技术发展受到了抑制。在这里，我们采用高角度环形暗场扫描透射电子显微镜 (HAADF-STEM) 结合二维能量色散 X 射线能谱 (2D EDX)，提供了一种新颖的纳米级机制视图。我们的结果表明，开关机制涉及到活性层中 Ti 和 O 离子的重新分布，以及有效形成导电丝的整体氧损失。我们的研究通过直接 EDX 映射显示了 TiO2 薄膜中钛的移动，这为提高基于 TiO2 的电阻随机存取存储器 (RRAM) 的鲁棒性和寿命提供了可行的起点。
