Study On The Transition Mechanism Of Ag/a-SiO₂/Pt Structure Resistance-variable Memory

In the 1920s,after three industrial revolutions,science and technology developed rapidly,and intelligent products emerged one after another.Some new technologies such as artificial intelligence,automobile electronics,Internet of things,virtual reality technology and so on emerged in endlessly.With the rapid development of information technology,people's ability to process information has been gradually improved,showing an explosive growth trend.On the other hand,the storage capacity of information also has a high demand,the traditional memory has not been able to meet the needs of people.There are many limitations and defects in traditional memory,in order to deal with these limitations,a variety of new memory,such as ferroelectric memory,magnetoresistive memory,phase change memory and resistive memory?RRAM?,emerged as the times require.These new types of memory are widely used in memory technology,solid-state disks and neurons,memory-integrated devices and so on.Among them,the resistance-change memory based on oxide semiconductor materials has been paid more and more attention.The resistance variable memory has the advantages of simple structure,high storage density,high speed of reading and writing,low power consumption,good micro-compressibility,compatibility with CMOS process and easy to realize 3D integration.It has been more than 50 years since the initial research of the resistive memory,but the mechanism of the resistive variable memory is still not clear,and there are still many shortcomings.At present,two mainstream explanations of the physical mechanism of conductive filament are accepted:one is the metal conductive filament channel based on the migration of metal elements;Secondly,based on the generation and migration of oxygen vacancies,conductive filament channels of oxygen vacancies are formed.In this paper,the first-principle method will be used.From the microscopic point of view,the mechanism of resistive variable memory is studied systematically.The main purpose of this paper is to calculate,simulate,simulate and analyze the RRAM device based on Ag/a-Si0₂/Pt structure.In order to study the formation process of conductive filament in RRAM devices with Ag/a-SiO₂/Pt structure,the amorphous SiO₂?a-SiO₂?model and Ag/a-SiO₂ interface model were constructed by using the CASTEP module of Material Studio software.On the basis of this,the energy band,density of state and electron cloud density of SiO₂ crystal and amorphous SiO₂ are calculated,and their electronic properties are analyzed.The results show that the SiO₂ crystal can be turned into amorphous by annealing at high temperature,and at this time,the energy band,state density and electron cloud density of SiO₂ crystal and amorphous Si0₂ crystal can be changed into amorphous.It changes from insulator to semiconductor.Then the migration barrier and formation energy of Ag ion in amorphous SiO₂ and the effect of applied electric field on the migration of Ag ion and temperature on the migration of Ag ion were studied.Finally,according to the ion migration characteristics,the difficulty of forming conductive filament of RRAM device Ag based on Ag/a-SiO₂/Pt structure is analyzed.The results show that the migration barrier of Ag ion in a-SiO₂ is small,and it is easy to form conductive filament.The effect of electric field on the migration of Ag ion can be ignored,and the migration of Ag ion is promoted by increasing temperature.In addition,the influence of doping effect of Ag,Cu on the ion migration of Ag was studied.We found that doping can promote the migration of Ag ions.Then we construct the interface model of Ag/amorphous SiO₂ and analyze its characteristics by simulation calculation and analysis so as to further understand the mechanism of conducting filament formation in RRAM devices with Ag/a-SiO₂/Pt structure.The optimal path of diffusion of Ag ions in the Ag/a-SiO₂ interface was found by means of transition state search for?Transition State Search,TS search?,and the formation mechanism of conductive filaments was determined.By studying the effect of the interface on the migration barrier,we found that the interface promoted the diffusion of Ag ions.At the same time,considering the formation process of conductive filament,we also studied the effect of doped Ag on the diffusion of Ag ions and the diffusion characteristics of multiple Ag ions at the same time.Based on this,the mechanism of conducting filament formation in RRAM devices with Ag/a-Si0₂/Pt structure is further analyzed.In conclusion,the micro-angle of the formation mechanism of the conductive filament of the RRAM device based on the Ag/a-SiO₂/Pt structure is discussed,and the formation mechanism of the RRAM conductive filament based on the metal element conductive filament is explained,and a certain theoretical guidance can be provided for the experimental research.In the first chapter,the classification and research status of the memory and the problems facing are described,and the significance of this paper is described.In the second chapter,the working mechanism of the resistive random access memory is introduced in a comprehensive and detailed way,and the research background and the theoretical foundation of this paper are introduced from the aspects of working principle,material,structure and so on,and the research methods of this paper are also introduced.In the third chapter,the electron characteristics of a-SiO₂ and the diffusion characteristics of Ag ions in a-SiO₂ are studied,and the influence of the doping effect on the diffusion of Ag ions is studied.In the fourth chapter,the Ag ion diffusion in the Ag/a-SiO₂ interface is studied in detail.Finally,the fifth chapter summarizes the work of this paper and the prospect of the future work.