ZnO基自整流忆阻器的制备及性能研究

发布时间：2018-03-06 08:03

本文选题：忆阻器　切入点：氧化锌　出处：《江苏大学》2017年硕士论文　论文类型：学位论文

【摘要】：忆阻器是一种两端器件,它能够实现不同电阻态之间的快速转换,并且制备过程与现有的CMOS工艺兼容,在信息存储和神经突触模拟方面有着独特的优势。为了提高器件集成度,忆阻器往往采用交叉阵列结构制备,从而存在串扰电流问题,通常在电路中串联二极管、晶体管等选通元件来抑制串扰电流,但是,这不可避免会严重限制器件的集成度。较为理想的办法是通过忆阻器自身的整流特性来抑制电路中的串扰电流。本文采用ZnO作为阻变材料,首先研究二极管(D)和忆阻器(R)串联结构的整流和忆阻行为,其次重点研究自整流忆阻器件。主要研究内容和结果如下:(1)1D1R结构的制备及性能研究。采用磁控溅射法制备多晶ZnO薄膜和铝掺杂的ZnO(AZO)薄膜。分析了溅射功率、溅射时间、腔体本底真空、氩氧比等工艺参数对ZnO薄膜电学性能的影响,发现氩氧比对于薄膜电阻转变性能有很大影响,Ar:O2为8:2时,ZnO薄膜的电阻转变特性最优。以Pt/ZnO/Pt作为忆阻器(R),Pt/AZO/ZnO/Pt作为肖特基二极管(D),通过串联构建了1D1R结构,该结构具有单极性电阻转变特性的同时,还能一定程度抑制负向电流。然而1D1R结构制备过程较为复杂,并且器件性能较差。(2)Ti/ZnO/Pt自整流忆阻器件制备及性能研究。一般来说,由于Pt功函数和ZnO电子亲和势之间的差异,Pt与ZnO之间属于肖特基接触。本文对Pt/ZnO/Pt在Ar气氛中进行快速退火,发现由于ZnO中氧空位的增多,Pt与ZnO之间可以实现准欧姆接触。类似地,对于Ti/ZnO/Pt结构,Ti/ZnO界面处会天然形成TiOx薄层,Zn O中氧空位增多,导致ZnO/Pt形成准欧姆接触。而对于Ti/ZnO界面,由于多晶薄膜易吸附空气中水汽,对界面接触性质产生很大影响,导致Ti/ZnO表现出明显肖特基接触行为,因此Ti/Zn O/Pt原始态器件表现出自整流特性。但是器件Forming以后自整流效应消失或明显减弱,因此无法解决电路中的串扰电流问题。(3)Ti/ZnO/AZO/Pt自整流忆阻器件制备及性能研究。通过器件结构及工艺参数优化,制备出了基于Ti/ZnO/AZO/Pt结构的自整流忆阻器。该自整流器件表现出无Forming以及非易失的双极性忆阻特性,同时具有很好的耐疲劳特性,开关比为102。通过对器件I-V曲线进行拟合分析,结合变温测试,发现Ti/ZnO/AZO/Pt器件忆阻行为属于纯电子效应,其导电行为来源于空间电荷限制电流或肖特基发射机理。在此基础上模拟了生物神经突触的长程可塑性以及学习-遗忘-再学习经验式行为。结果表明,Ti/ZnO/AZO/Pt自整流忆阻器能很好解决电路中的串扰电流问题,因此在存储器和神经突触器件方面具有潜在的应用价值。
[Abstract]:The memristor is a device at both ends, it can realize the fast conversion between different resistance state, and preparation process is compatible with the existing CMOS process, the information storage and synaptic simulation has a unique advantage. In order to improve the device integration, the memristor often adopts the cross array structure and preparation. The presence of crosstalk current problems, usually in the circuit in series diode, transistor gate element to suppress crosstalk current, but it will inevitably restrict the integration of device. The ideal way is to suppress the crosstalk current in the circuit through a rectification characteristic of the memristor itself. This paper uses ZnO as the resistive material, first of all study on diode (D) and the memristor (R) series structure rectification and memristive behavior, then focus on the self rectifying memristive device. The main research contents and results are as follows: (1) preparation and performance of 1D1R structure. The. Prepared by magnetron sputtering of polycrystalline ZnO thin film and aluminum doped ZnO thin film (AZO). Analysis of the sputtering power, sputtering time, the effect of vacuum cavity bottom, argon oxygen ratio and other parameters on the electrical properties of ZnO thin films, found that the ratio of argon to oxygen has a great influence on the performance of Ar:O2 thin film resistance change, 8:2 when the optimal resistance switching properties of ZnO thin films. Using Pt/ZnO/Pt as the memristor (R), Pt/AZO/ZnO/Pt (D), as a Schottky diode 1D1R structure constructed by series, this structure has the characteristics of change of unipolar resistance at the same time, but also a certain degree of inhibition of the negative current. However, the structure of 1D1R preparation process is complex, and the performance of the device is poor. (2) research and preparation of Ti/ZnO/Pt resistance device performance self rectifying memory. In general, due to the work function of Pt and ZnO electron affinity difference between potential, belongs to the Schottky contact between Pt and ZnO. The Pt/ZnO/Pt in Ar atmosphere In the fast annealing, found that due to the increase of oxygen vacancies in ZnO, between Pt and ZnO can realize quasi ohmic contact. Similarly, for the Ti/ZnO/Pt structure, Ti/ZnO interface will naturally formed TiOx layer, oxygen vacancy of Zn O increased, leading to ZnO/Pt formation of quasi ohmic contact. For the Ti/ ZnO interface, the polycrystalline thin film easy to absorb moisture in the air, have a great impact on the interface properties, resulting in Ti/ZnO showed obvious Schottky contact behavior, so the Ti/Zn O/Pt devices from the original state. But after rectifying characteristic device Forming self rectifying effect disappeared or significantly decreased, so it can not solve the current problem of crosstalk in a circuit. (3) study and performance of resistance device preparation of Ti/ZnO/AZO/Pt self rectifying memory. Through the device structure and process parameters optimization, was prepared by self rectifying memristor based on Ti/ZnO/AZO/Pt structure. The self rectifying devices showed no Forming As well as non bipolar memristor characteristics of volatile, and has good anti fatigue properties, switch ratio is 102. by fitting analysis of I-V curve with a temperature testing device, Ti/ZnO/AZO/Pt device, the memristor behavior belongs to the pure electronic effect, the conductive behavior from the space charge limited current or Schottky emission mechanism based. On the simulation of the biological neural synaptic plasticity and long-term learning forgetting - learning experience behavior. The results show that the Ti/ZnO/AZO/Pt rectifier memristor can solve the problem of crosstalk current in the circuit, so it has potential application value in memory and synaptic devices.

【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】：TN60

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