阻变式存储器性质的研究

发布时间：2018-08-31 20:37

【摘要】：随着科学技术的进步，半导体制造工艺水平的提高，信息产业得到了快速发展。信息存储作为信息技术的一部分也得到了空前进步，存储器正朝着集成度不断提高、外观更加精巧、重量更轻、存取速度更快、存储容量不断增大的方向发展。传统意义上的存储器是基于晶体管对电荷的存储而制造的，许多时候无法满足信息技术迅速发展的需要，因此寻找一种高密度、非挥发性，低功耗的下一代存储器已经迫在眉睫。现阶段更多的研究者们把关注的重点放在非易失性存储器上，例如铁电存储器，磁存储器，相变存储器、电阻存储器。在这些存储器中，阻变存储器因自身的许多优点普遍受到了人们的广泛关注，它具有结构简单、读写速度快、制造成本低、功耗低、单个器件可缩小至数十纳米等特点，在众多的绝缘材料和半导体材料中纷纷发现这种新奇的电阻开关效应。随着研究的不断进行，我们发现了阻变存储器许多新的有趣的现象：单极性电阻开关和双极性电阻开关在一定的限制条件下可以相互转化；阻变存储器电学性质I-V曲线的顺时针旋转和逆时针的旋转受到电形成过程的影响，可以通过控制电形成过程来控制其旋转方向；我们在阻变存储器的研究中发现了无极性电阻开关和非常规双极性电阻开关的存在，同时得出非常规双极性电阻开关在合适的条件下可以转化为常规性双极性电阻开关。这些现象的发现能够为研究者更全面的了解电阻开关的形成机制提供很好的帮助。然而迄今为止，还没有哪一个理论模型能对这些现象作出一个完整清晰的解释，理论分析还比较欠缺，仍有大量工作要做。本论文通过激光脉冲技术(PLD)制备了薄膜电阻开关器件，通过改变衬底条件，引入光照等方法来具体研究阻变存储器的机制，另外，本人在对电阻开关实现逻辑门电路的研究中有些新的想法和研究结果。本论文主要内容包括以下几个方面： 1．采用脉冲激光沉积技术制备了Au/STO/Pt结构的阻变存储器件，通过X射线衍射仪(XRD)、扫描电子显微镜(SEM)、原子力显微镜(AFM)分析薄膜的特性。之后应用Keiythley2400对阻变器件进行电学性能测试，在经历了Electroforming电压操作后，阻变器件表现出良好的开关性能，包括较低的阈值电压、良好的抗疲劳性和保持特性。根据测得的电学性质I-V曲线，应用缺陷和氧空位之间捕获和去捕获理论来解释所得到的双极性电阻开关性质。另外，根据双极性电阻开关的特点和优势，构造适当的逻辑值，在前人的基础之上，利用简单的阻变存储器来实现数据存取，结合现代随机存储器的结构和新型阻变存储器的工艺，实现新型阻变存储器的构造，并将阻变存储器与晶体管存储器进行简单的比较，在芯片功能，引脚作用，如何实现存储方面进行了介绍。 2．制备了Au/Nb:STO/Pt和Au/Nb:STO/FTO三明治结构阻变存储器，通过各种表征手法分析两种存储器结构上的异同，分别测量它们的电学I-V曲线，由于衬底的不同曲线趋势会有明显差异，对阻变存储器的性质产生了一定影响，，这是因为，肖特基势垒在阻变开关现象中起到了重要作用。使用LED阵列灯光对器件进行照射，观测两种不同器件在光照后表现出来的共同特征，并根据理论基础解释这个现象。通过不同的激发电压和限制电流来实现阻变开关器由双极性向单极性的转换，同时，我们知道如果设置限制电流在使在第一个形成过程产生了足够的热量，同样可以使电阻开关达到金属导电丝的低电阻状态，器件会立刻产生单极性电阻开关的性质。根据一系列的实验结论，结合前人提出的理论模型，对阻变存储器的机制进行全面的分析和解释。
[Abstract]:With the development of science and technology and the improvement of semiconductor manufacturing technology, the information industry has developed rapidly. As a part of information technology, information storage has also made unprecedented progress. Traditionally, memory is based on the transistor's charge storage, which can not meet the needs of the rapid development of information technology in many cases. Therefore, it is urgent to find a high density, non-volatile, low-power next-generation memory. Among these memories, resistive memory has attracted much attention because of its many advantages, such as simple structure, fast read-write speed, low manufacturing cost, low power consumption, single device can be reduced to tens of nanometers, and so on. This novel resistance switching effect has been found in materials and semiconductors. With the development of research, many interesting new phenomena have been discovered: unipolar resistance switches and bipolar resistance switches can be transformed into each other under certain restrictive conditions; the electrical properties of resistive memory I-V curves are clockwise. Needle rotation and counterclockwise rotation are affected by the electric forming process, and the direction of rotation can be controlled by controlling the forming process. We found the existence of non-polar resistance switch and unconventional bipolar resistance switch in the research of resistance-variable memory, and obtained that unconventional bipolar resistance switch can be used under appropriate conditions. The discovery of these phenomena can help researchers to understand the formation mechanism of resistance switches more comprehensively. However, so far, no theoretical model can give a complete and clear explanation for these phenomena. Theoretical analysis is still lacking, and much work remains to be done. In this paper, thin film resistive switching devices are fabricated by laser pulse technology (PLD). The mechanism of resistive memory is studied by changing substrate conditions and introducing illumination. In addition, I have some new ideas and research results in the research of resistive switching logic gate circuit. Noodles:
1. The resistive memory devices with Au/STO/Pt structure were fabricated by pulsed laser deposition. The properties of the films were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The electrical properties of the resistive devices were tested by Keiythley 2400. After the operation of the electroforming voltage, the resistive devices were tested. It shows good switching performance, including low threshold voltage, good fatigue resistance and retention characteristics. According to the measured electrical properties I-V curves, the obtained bipolar resistance switching properties are explained by the theory of trapping and de-trapping between defect and oxygen vacancy. When the logic value, on the basis of predecessors, using a simple resistive memory to achieve data access, combining the structure of modern random access memory and new resistive memory technology, to achieve a new resistive memory structure, and resistive memory and transistor memory for a simple comparison, in the chip function, pin role, how The storage aspect is introduced.
2. Au/Nb:STO/Pt and Au/Nb:STO/FTO sandwich structure resistive memory are fabricated. The similarities and differences between the two memory structures are analyzed by various characterization methods. The electrical I-V curves of the two memory structures are measured respectively. The different trend of the substrate curves will have obvious differences, which has a certain impact on the properties of resistive memory because of Schottky potential. The barrier plays an important role in the resistance switching phenomenon. The LED array lamp is used to illuminate the device and observe the common characteristics of the two different devices after illumination. We know that if the limiting current is set to generate enough heat in the first formation process, the resistance switch can also be made to the low resistance state of the metal conductive wire, and the device will immediately produce the properties of the unipolar resistance switch. The mechanism is comprehensively analyzed and explained.
【学位授予单位】：河南大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TP333

【参考文献】