Research On Performance And Mechanism Of Resistive Access Memory Based On SiN_x

With the rapid development of science and technology,novel intelligent electronic devices increase the demand of high quality information storage method.The traditional Flash technology has reached its physical limit.Thus finding the next generation of non-volatile memory has become research hotspots.Among these new non-volatile memories,resistive random access memory?RRAM?is considered as a promising candidate for replacing Flash due to its advantages like simple structure,low power consumption,high density,and compatibility with the standard CMOS process,which make it as a hotspot in this research field.In this paper,we studied SiN_x-based RRAM.The main research content is as follows:1.Firstly,we systematically analyzed the advantages and disadvantages of conventional memory.And we listed several memory devices which can instead of conventional devices.Then we discussed the excellent properties as a novel memory device.Subsequently,we made a brief discussion of the research background of RRAM.Also,we made a detailed explanation of materials and physical mechanism of RRAM.2.Then,we utilized COMSOL Multiphysics^TM to simulate the operation mechanism of W/SiN_x/Pt RRAM in this paper.Based on the three partial differential equations of ion migration,electrical conduction and Joule heating,we established an electro-thermal coupling model.In this model,we can solve the distribution changes of nitrogen vacancy concentration,potential and temperature during the conversion process by changing the materials'parameters,boundary conditions and mesh size.Also,we analyzed the reasons of the parameters changes in Set/Reset processes.We confirmed that temperature and electrical field play important roles in resistance changing process.In addition,by considering simulation results with experiments we proposed that the operation mechanism of this device is based on the quantity of silicon dangling bonds?Si-DBs?in functional layer.Due to the changes in the composition of silicon nitride film materials can affect the devices'performance.Here we analyzed the resistance changing properties of SiN_x in different stoichiometric ratio.This study has a reference value for improving the performance of RRAM.3.In this paper,the growth of the conductive filament based on electrochemically conductive in RRAM has been simulated by MATLAB.By analyzing the particles transport in functional layer,we established the Ag/SiN_x/Pt RRAM one-dimensional numerical model by combining the ion transport and boundary conditions.Then we obtained the growth mechanism of conductive filament in forming process by solving a series of partial differential equations.The simulation results expressed that this ion transport model can achieve the conductive process in RRAM.Subsequently,we utilized kinetic Monte Carlo method to establish the morphology,state and charge matrixes to update the 2-dimentional growth of the conductive filament in the functional layer.This simulation helped us intuitionally observe the conductive filament's growth in the functional layer.And this result shows that kinetic Monte Carlo method can achieve the forming process of RRAM.Also,we found that the growth of the conductive filament can be effective optimized by prior deposition of metal nanostructure at the cathode surface.These results have reference values in promoting the properties of these devices.In addition,we combined experimental results and proposed that the resistance changing mechanism of Ag/SiN_x/Pt RRAM is the oxidation-reduction reaction of Ag⁺.And the conductive filament is metallic.A good RRAM model and analysis of RRAM operation mechanism are of great significance for the development of RRAM.