Department of Materials Science and Engineering and Inter-University Semiconductor Research Center, Seoul National University, Seoul 151-744, Republic of Korea.
Nanoscale. 2017 Aug 24;9(33):11920-11928. doi: 10.1039/c7nr02215h.
To replace the present NAND flash memory, resistance switching random access memory (ReRAM), which has both memory and selection functionalities with a simple metal-insulator-metal structure should be implemented. To accomplish this goal, ReRAM must be self-rectifying, low-power-consuming, and highly uniform, and it must have reliable states. In this work, the Pt/TiO/HfO/TiN resistive switching memory structure showed self-rectifying resistive switching behavior with unprecedented unique I-V curves. This is named "self-current saturation," which can give an extremely uniform variation of the low resistance state. The plausible reasons for the whole switching behavior, including the unique I-V curves, in this material system are presented herein. The diffusion of Ti along the grain boundaries of HfO down to the bottom electrode TiN and the defect formation within the HfO layer near the TiO/HfO interface made the resistance switching device have the characteristics of both the unidirectional diode and electronic bipolar switching devices.
为了取代现有的 NAND 闪存，应该采用具有简单金属-绝缘体-金属结构的电阻式随机存取存储器 (ReRAM)，它同时具有存储和选择功能。为了实现这一目标，ReRAM 必须具有自整流、低功耗和高度均匀性，并且必须具有可靠的状态。在这项工作中，Pt/TiO/HfO/TiN 电阻式开关存储结构表现出自整流电阻式开关行为，具有前所未有的独特 I-V 曲线。这被命名为“自电流饱和”，它可以给出极低电阻状态的极其均匀的变化。本文提出了该材料系统中整个开关行为（包括独特的 I-V 曲线）的可能原因。Ti 沿着 HfO 的晶界扩散到底部电极 TiN，以及在 TiO/HfO 界面附近的 HfO 层内形成缺陷，使得电阻开关器件具有单向二极管和电子双极开关器件的特性。
