Study On RAAM Device Based On Finite Element Method

In the information age,with the increasing market demand for data storage and data transmission,people’s requirements for the storage devices are becoming more and more demanding.Because of its excellent performance,new non-volatile memory gradually comes into people’s field of vision.Among them,the resistive random access memory（RRAM）has many advantages such as simple structure,high integration,high tolerance,low power consumption,fast switching speed,strong compatibility with CMOS technology and so on,that caused the extensive concern of academic circles.Due to the problems such as large limitation of observation equipment,uncontrollable variables and large consumption of consumables in pure physical experiments,the influence of different variables on RRAM performance and its application in integrated circuits may be studied from the macro and micro levels by means of simulation modeling.In this thesis the RRAM is studied based on the finite element method,and the model of RRAM is built to study the electrical performance,thermal performance and particle motion state under different conditions.And the effect of oxygen vacancy movement rate on RRAM performance was studied.Besides,the influence of leakage current is reduced by building a 1S1R model.First,a simulation model of TiO₂ based RRAM was built based on the theory of conductive filament,and then the basic characteristics of RRAM,and the regulation of resistance layer and electrode layer were studied.After the physical electro-thermal model was built by the finite element method,the electrical performance,thermal performance and particle distribution inside the device during the SET and RESET process of RRAM were studied.Result in the conductive filament（CF）including disconnection and formation in RRAM was analyzed,that verifies the validity of the model.Then,the influence of resistive layer thickness and top electrode conductivity on the performance of RRAM devices was studied,which provides reference for the selection of process and materials.Then,the effect of oxygen vacancy movement rate on RRAM performance was studied.After applying the pulse voltage to the RRAM model,the model performance was analyzed.Then the influence trend of oxygen vacancy migration and diffusion rate on RRAM performance was initially obtained.In order to further verify the relationship between oxygen vacancy movement rate and CF growth in RRAM,the waveform of scanning voltage was changed.Then the research results were applied to a new device model,and the optimized simulation model was built to provide innovative solutions for experiments.Finally,a TiO₂ based 1S1R simulation model was built,and the basic characteristics of the model and the relationship between the functional layer and performance of the model were studied.If the RRAM is applied in integrated circuit,in order to reduce the crosstalk effect caused by leakage current,it can be realized by building 1S1R components.Above all,a threshold switching device model was built.After confirming the switching characteristics of the threshold switching device model,a 1S1R model was further built to study the basic characteristics of the model.Finally,the effect of the thickness of transition layer and intermediate Pt layer on the performance of 1S1R was studied.It provides the simulation basis for RRAM application in integrated circuit.