Theoretical Investigation Of The Filament Morphology In Conductive Bridge Random Access Memories

Conventional memories that use charge as a storage medium face the problem of physical limit as the size of the process shrinks.Therefore,it is necessary to research a new type of non-volatile memory.The resistive random access memory?RRAM?is one of the candidates for the next generation of non-volatile memory due to its simple structure,easy integration and low power consumption.Among them,the conductive bridge resistive random access memory?CBRAM?has the characteristics of fast response,good cycle characteristics and multi-value storage,and has become one of the hotspots of research on RRAM.Understanding and controlling the growth of metallic conductive filaments is critical in neural morphology calculations and artificial neural network applications.At the same time,the research on the mechanism of metal conductive filaments also contributes to the commercial production and application of CBRAM.In this dissertation,the first principle used to research the formation mechanism of metal conductive filaments in CBRAM.First,combined with the existing experimental results,we explored the physical mechanism behind the different growth modes of Ag conductive filaments in GeSe,ZrO₂,SiO₂ and a-Si.It is found that the stability,migration barrier and polarization of Ag⁺in the material play a key role in the growth mode of the conductive filaments.Based on this,we explain the growth mode of the conductive filaments in the four materials,especially the different growth patterns of the conductive filaments in the SiO₂ prepared by sputtering and PECVD.Secondly,based on the analysis of Ag conductive filaments,we modeled and analyzed the growth mode of Ni conductive filaments in these four materials.It is found that the stability,migration barrier and polarization properties of Ni ions in the material are similar to those of Ag,so we predict that the growth pattern of Ni conductive filaments in the four materials is the same as that of Ag conductive filaments.Finally,combined with the analysis of Ag and Ni conductive filaments,we believe that the functional layer material in CBRAM is a key factor affecting the growth mode of metal conductive filaments,and the influence of metallic conductive filament materials is small.