Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA 19104-6272, USA.
Nanoscale. 2016 Oct 27;8(42):18113-18120. doi: 10.1039/c6nr06427b.
Resistance random access memory (RRAM) is a rapidly developing emergent nanotechnology. For practical applications and basic understanding, it is important to ascertain whether RRAM undergoes uniform or filamentary switching, but on this point previous area-scaling studies have often shown ambiguous and conflicting findings. Here we demonstrate a simple test-physically breaking the device into two and studying their characteristics individually-can make a definitive determination. Our experiment on two prototypical RRAMs found that one (the nanometallic memory) switches and conducts uniformly while the other (the filamentary memory) does not. It also probes the statistics of nanofilaments: the resistance statistics of the filamentary memory reveals for the first time a large population of partially developed filaments in addition to the filament that dominates switching. Remarkably, the filamentary memory can also be stress-switched to a lower resistance state during fracture, which is reminiscent of stress-switching of the nanometallic memory and may be taken as direct evidence of electron-phonon interaction in the filaments.
阻变随机存储器（RRAM）是一种快速发展的新兴纳米技术。为了实际应用和基础理解，确定 RRAM 是否经历均匀或细丝开关至关重要，但在这一点上，以前的面积缩放研究经常显示出模糊和相互矛盾的结果。在这里，我们展示了一种简单的测试方法——物理上将器件一分为二，并分别研究其特性——可以做出明确的判断。我们对两种原型 RRAM 的实验发现，一种（纳米金属存储器）均匀地开关和导通，而另一种（细丝存储器）则不这样。它还探测了纳米丝的统计特性：细丝存储器的电阻统计首次揭示了除了主导开关的细丝之外，还有大量部分发展的细丝。值得注意的是，细丝存储器在断裂过程中也可以被应力切换到较低的电阻状态，这让人联想到纳米金属存储器的应力切换，这可能被视为细丝中电子-声子相互作用的直接证据。
