Research On Resistive Switching Properties Of ZnO/BiFeO₃ Bilayer Films

With the rapid development of the industrialization of electronic information technology,people put forward higher requirements for memory performance.The demand for equipment miniaturization,high density,fast reading and writing,and longevity has been driving technological innovation.Nonvolatile memory?NVM?equipment,with its excellent performance,has been more and more popular and supported by researchers.As a commonly used NVM device,silicon based flash memory has a wide range of applications.However,the relative short lifetime,slow reading and writing speed and other bottlenecks have greatly restricted its application prospects.As an alternative,a number of new NVM devices have emerged,including ferroelectric random access memory?FeRAM?,phase change random access memory?PRAM?,and barrier random access memory?RRAM?.Among these new types of memory,RRAM has attracted more and more researchers' attention for its superior storage performance,and is considered as the most promising alternative to traditional memory.Bismuth ferrite BiFeO₃?BFO?is a representative type of single-phase multiferroic material.As a perovskite structure with ferroelectric and ferromagnetic properties at room temperature,its unique properties make it widely used in nonvolatile memory and other fields.However,its large leakage current limits its application.The leakage current of BFO thin film can be reduced by adding suitable layer to construct multilayer film structure.ZnO,as a class of common semiconductor,has outstanding characteristics in many aspects,such as photoelectricity,piezoelectricity,and so on.It can be used as a buffer layer.This paper combines them to investigate the barrier properties of ZnO/BFO bilayers,as outlined below:1.Firstly,the basic properties and research progress of ZnO and BFO are introduced,and then the basic knowledge of resistance switching effect is introduced,including the classification of switches and the explanation of conduction mechanism.2.Briefly introduce the common methods of preparing films and their principles and characteristics,mainly including two categories: physical,meteorological and chemical vapor deposition.The knowledge of magnetron sputtering and some methods for characterizing samples are introduced.3.Briefly describes the experimental process,including the preparation of samples by vacuum magnetron sputtering and annealing at different temperatures.The crystal structure of the samples is studied by XRD.The results show that the samples are well crystallized.4.The resistance switch performance of sample is discussed in detail,including stability,high and low resistance ratio and so on.The influence of different light intensity on its characteristics was also compared,5.The mechanism of resistance switching effect is explained.The results show that the ZnO/BiFeO₃ sample had resistance switching effect,and the regulation of the light,and light current increased,the resistance switching effect has also been a corresponding increase,also decreases the voltage setting.The high and low drag ratio also increases correspondingly.The sample has a certain stability and no obvious deterioration in the lap test.Finally,the conduction mechanism of current is analyzed by curve fitting.It is found that the main source of resistance switch is the polarization reversal of BFO layer,which results in the change of interface barrier.