Ismail Muhammad, Hashmi Arqum, Rana Anwar Manzoor, Kim Sungjun
School of Electronics Engineering, Chungbuk National University, Cheongju 28644, Republic of Korea.
Nanotechnology. 2020 Aug 7;31(32):325201. doi: 10.1088/1361-6528/ab8b8e. Epub 2020 Apr 21.
Memristors, with low energy consumption, long data storage and fast switching speed, are considered to be promising for applications such as terabit data storage memory and hardware based neurocomputation applications. However, unexpected negative-Set behavior is a serious issue that causes deterioration of reliability and uniformity of switching parameters. In this work, negative-Set behavior of TiO-based RRAM is successfully eradicated by inserting a thin oxygen vacancy rich ZrO layer. In addition, oxygen vacancy rich ZrO layer is also responsible for the enhancement of resistive switching characteristics in terms of excellent endurance performance (2000 DC cycles), good data retention upto 10 s and uniformity in Set/Reset voltages. Experimental results and density functional theory (DFT) analysis confirm that an interface layer TiO has formed between highly reactive electrode (Ti) and ZrO interlayer. This interface layer is serving as a low series resistance layer and oxygen ion reservoir in Set-process and oxygen ions supplier in Reset-process to generate/refill the oxygen vacancies in the formation and rupture of conductive filaments. Comparing with the single layer Ti/TiO/Pt device, it is noteworthy that the switching process in the bilayer (BL) Ti/ZrO/TiO/Pt memristor device is not affected even at high Reset-voltages, but the negative-Set behavior has been eradicated effectively. This work demonstrates that the insertion of a thin oxygen vacancy rich ZrO interlayer into TiO-based devices is a feasible approach to solve unpredicted negative-Set behavior of RRAM devices.
忆阻器具有低能耗、长数据存储和快速开关速度的特点，被认为在太比特数据存储内存和基于硬件的神经计算应用等领域具有广阔的应用前景。然而，意外的负置行为是一个严重的问题，会导致开关参数的可靠性和均匀性下降。在这项工作中，通过插入一层富含氧空位的薄ZrO层，成功消除了基于TiO的阻变随机存取存储器（RRAM）的负置行为。此外，富含氧空位的ZrO层还在出色的耐久性（2000次直流循环）、高达10秒的良好数据保持能力以及置位/复位电压的均匀性方面，对电阻开关特性的增强起到了作用。实验结果和密度泛函理论（DFT）分析证实，在高反应性电极（Ti）和ZrO中间层之间形成了界面层TiO。该界面层在置位过程中充当低串联电阻层和氧离子储存库，在复位过程中充当氧离子供应源，以在导电细丝的形成和断裂过程中产生/补充氧空位。值得注意的是，与单层Ti/TiO/Pt器件相比，即使在高复位电压下，双层（BL）Ti/ZrO/TiO/Pt忆阻器器件的开关过程也不受影响，但负置行为已被有效消除。这项工作表明，在基于TiO的器件中插入一层富含氧空位的薄ZrO中间层是解决RRAM器件不可预测的负置行为的一种可行方法。
