Research On Resistive Switching Memory Based On Stack Structure

In the process of semiconductor industry to 20nm technology node or smaller direction,the memory industry is facing many challenges in terms of technology and materials.As size shrinks,the storage density of traditional nonvolatile memory based on silicon material has been closer to its intrinsic limit.RRAM relies on resistance rather than charge changes to store information,and its many advantages can meet the requirements of future high-speed,ultra-low power,nano-space storage devices,attracting the attention of researchers around the world.In this paper,the RRAM of the stack structure is studied.The main contents are as follows:1.In this paper,COMSOL simulation software was used to simulate thedistribution of oxygen vacancyconcentration,temperature and electric field in the process of resistance conversionof Pt/HfO₂/TiO₂/Pt RRAM.The electro-thermal coupling model obtains the distribution of each parameter by solving a series of partial differential equations.And the influence of the structure on the oxygen vacancy concentration and on the distribution of conversion voltage is simulated and analyzed,which can provide reference for the analysis of the mechanism and the optimization of the performance.The establishment of the stacked structure model has a positive effect on the further understanding of the operating mechanism of the RRAM device and the optimization of the device reliability.2.In this paper,Pt/TiO₂/TiO_x/Pt RRAM devices were prepared by PVD equipment,and the reliability of the devices was improved by optimizing the oxygen-argon ratio parameters?oxygen-argon ratio changingfrom 10%to 20%?in the preparation process and introducing oxygen vacancies.As the composition and quality of the film play a key role in the performance of the device,and in the process of thin film deposition,oxygen flux is an important process parameter,so optimizing the oxygen and argon process parameters can effectively improve the performance of the device.In a certain range,the introduction of oxygen vacancy defects has a positive effect for the practical application of RRAM devices because it can reduceconversion voltage and power consumption.3.In this paper,the preparation and electrical properties of Pt/HfO₂/HfO_x/Pt RRAM devices were studied.When the filament is initially formed,it is necessary to control the maximum current to prevent the formation of irreversible thermodynamic dielectric breakdown.However,current overshoot effects usually occurredin the resistance conversion process of HfO₂-based RRAM device,making the device breakdown and no reset process.So how to eliminate the current overshoot effect and preparing RRAM device with good conversion performance will be one of the focuses of the study.The change of film thickness and the introduction of oxygen vacancy?oxygen-argon ratio changingfrom 15%to 100%?can change the film quality and film composition.This paper improves the current overshoot effect by optimizing the oxygen-argon ratio and thickness of the device to improve the film quality.