ZnO薄膜和纳米线阻变存储器制备、性能及机理研究

发布时间：2018-04-10 16:36

本文选题：电阻型存储器 + 阻变　；参考：《江苏大学》2017年硕士论文

【摘要】：随着电子器件尺寸的缩小,传统的Flash非挥发性存储器遇到了漏电等一系列难题,严重阻碍了其发展。而基于电致电阻效应的阻变存储器(RRAM)具有非易失、结构简单、存储密度高、读写速度快、功耗低、与传统CMOS工艺兼容性好等优点,有望取代传统的存储器,因此受到广泛研究和关注。在众多的阻变材料中,由于Zn O材料具有价格便宜,成分简单,易制备等特点,因此Zn O材料是RRAM的理想候选材料之一。本文主要以Zn O薄膜材料和纳米线(NW)作为RRAM器件的阻变材料,研究了器件制备,阻变行为及相应的阻变机理,主要研究内容如下:(一)基于Zn O薄膜RRAM器件的研究研究了Cu/Zn O/Pt器件基于两种不同导电丝形成机制的阻变行为,即电化学金属化(ECM)机制和价变(VCM)机制。通过细致考察器件低阻态电阻随温度的变化关系,发现Cu/Zn O/Pt器件中VCM机制形成的导电丝成分是锌,ECM机制形成的导电丝成分是铜。通过形成不同成分的导电丝,实现了器件的多模式操作,并且发现器件的操作可以在两种不同阻变机制之间可逆稳定切换。(二)基于单根Zn O纳米线的RRAM器件的研究随着器件尺寸的不断缩小,基于一维纳米线的阻变存储器具有重要的研究价值。本文通过拉丝法制备了基于单根Zn O纳米线的Ag/Zn O NW/Ag RRAM器件,器件表现出双极性阻变特性,FORM(由初始态转变为低阻态的过程)电压一般大于10 V,SET(高阻态转变为低阻态的过程)和RESET(低阻态转变为高阻态的过程)电压相对较小并且集中,开关比(高阻态与低阻态的阻值之比)大于109,但器件抗疲劳(高低阻态之间可逆切换)特性较差。(三)基于银修饰单根Zn O纳米线的RRAM器件的研究为改善Zn O纳米线器件的阻变特性,采用光化学沉积法对Zn O纳米线表面进行银修饰,经过修饰后的器件阻变性能得到提升,FORM电压大幅降至3 V以下,高低阻态稳定性和抗疲劳特性均得到改善,进一步发现银修饰后,器件表现出多级存储现象。最后解释了银修饰纳米线器件性能提升的原因。
[Abstract]:With the reduction of electronic device size, the traditional Flash nonvolatile memory has encountered a series of problems, such as leakage, which seriously hindered its development.The resistive memory (RRAM) based on electroresistance effect has the advantages of non-volatile, simple structure, high storage density, fast reading and writing speed, low power consumption and good compatibility with the traditional CMOS process, which is expected to replace the traditional memory.As a result, it has received extensive research and attention.Zno is one of the ideal candidate materials for RRAM because of its low price, simple composition and easy preparation.In this paper, Zno thin film and nanowire NW) are used as the resistive materials of RRAM devices. The fabrication, the resistance behavior and the corresponding resistance mechanism of the devices are studied.The main contents are as follows: (1) based on ZnO thin film RRAM devices, the resistance behavior of Cu/Zn O/Pt devices based on two different kinds of conductive wire formation mechanisms, namely electrochemical metallization mechanism and valence shift mechanism, are studied.It is found that the component of conductive wire formed by VCM mechanism in Cu/Zn O/Pt device is copper by careful investigation of the change of low resistance state resistance with temperature.The multi-mode operation of the device is realized by the formation of conductive wire with different components, and it is found that the operation of the device can be switched steadily between two different resistance mechanisms.(2) the research of RRAM devices based on single Zno nanowires is of great value in the research of resistive memory based on one-dimensional nanowires with the decreasing of device size.In this paper, Ag/Zn O NW/Ag RRAM devices based on single ZnO nanowires were fabricated by wire drawing.The device exhibits bipolar resistive characteristics: the voltage of FORM (the process of transition from the initial state to the state of low resistance) is generally greater than 10 V set (the process of transition from high resistance to low resistance) and the voltage of RESET (the process of transition from low resistance to high resistance) is relatively small and concentrated.The switching ratio (the ratio of high resistance to low resistance) is greater than 109, but the fatigue resistance (reversible switching between high and low resistance states) is poor.(3) in order to improve the resistance of Zno nanowires, silver modification of ZnO nanowires was carried out by photochemical deposition in order to improve the resistance of ZnO devices based on silver modified ZnO nanowires.After modification, the voltage of form is greatly reduced to less than 3 V, and the high and low resistance state stability and fatigue resistance are improved. It is further found that after silver modification, the device exhibits multistage storage.Finally, the reasons for the improvement of the performance of silver modified nanowire devices are explained.
【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383;TP333

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