Preparation And Properties Of Memory Devices Based On Silver Ion Migration

As the fourth basic passive electronic component,the memristor has attracted widespread attention.Its advantages such as simple structure and easy integration have great application potential in the fields of non-volatile storage and synaptic biomimetic simulation.According to the characteristic of memristors,the memristors are divided into digital memristors and analog memristors.Among them,digital memristors are mainly used for non-volatile information storage and the nonlinear transmission characteristics of analog memristors are related to biological synapses.Highly similar,it is the best candidate to build a brain-like neural network.According to the in-depth research on the memristor,a variety of transformation mechanisms have been proposed and verified.Among them,the mechanism of conductive filaments based on the migration of silver ions has been explored in memristors of different materials.Therefore,this article hopes to successfully prepare a memristor based on the migration of silver ions.Resistance devices and the performance of the devices are studied,and their applications in data storage and nerve synapses are realized,respectively.The detailed research and results are as follows:1.In order to realize the resistance change characteristics of digital memristors,we used amorphous carbon,zinc oxide,amorphous silicon and other materials to prepare a series of memristors using magnetron sputtering for research.Then we compared the conversion voltage,window and other parameters.Later,we found that the performance of Pt/a-Si/Ag devices was significantly better than the other two devices,and a-Si was easily integrated with existing CMOS devices to realize large-scale integrated circuit design.Faced with the volatility problem of the device,the silicon-based memristor was optimized by inserting the AIST buffer layer,and the Pt/a-Si/Ag In Sb Te(AIST)/Ag device was successfully fabricated.Through physical characterization and electrical testing,the resistance fluctuation before and after optimization was found.The performance parameter decreased from 176.8%/46.2%to3.1%/11.9%,the volatility parameter of the transition voltage decreased from 47.4%/85.7%to5.7%/9.8%,and the cycle tolerance of the device was also significantly improved from 10~3times to greater than 10~4 times.At the same time,the device has the advantages of faster transition speed(10 ns),longer retention time(10 years),lower power consumption(15 fj),etc.The improvement in device performance can be attributed to:Ag storage in the buffer layer.The ability reduces the excessive migration of Ag ions during the resistive switching process and enhances the controllability of the morphology of conductive filaments.2.In order to achieve the resistance change characteristics of the analog memristor,we used magnetron sputtering and chemical synthesis to introduce metallic silver nanoparticles into silicon-based and organic materials,and successfully prepared Pt/Si:Ag/Ag devices.And Pt/PVDF:Ag/Ag devices can realize analog memristive function.In the process of research,we found that it is difficult to control the doping ratio of silver nanoparticles using magnetron sputtering method,which makes the resistance continuity of Pt/Si:Ag/Ag devices poor,and it is not conducive to the simulation of nerve synaptic function.The synthesis method can optimize the concentration of silver nanoparticles.After studying the devices with different doping concentrations,we found that when the doping concentration reaches 140 phr,the Pt/PVDF:Ag/Ag device exhibits good analog resistance characteristics,and the device is excited.We usually through precise control of the migration process of silver ions,the memristor can simulate the neurosynaptic plasticity,including EPSC,PPF,STDP,etc.In particular,the flexibility of organic materials can also make the device have better flexibility,fitability and other characteristics.