Simulation Of The Resistive Switching Memory Based On A New Oxygen Vacancy Model

In recent years, with the rapid development of portable electronic products and wearable devices, memory devices are also facing enormous challenges. The traditional Flash technology is closing to its physical size limit, and finding the next generation of non-volatile memory has become a hot research topic. In the new storage technology, the resistive memory behaves good performance: simple structure, low operation voltage, high writing speed, good endurance, long retention time, and be compatible with the standard CMOS process, etc.. At present, it is a very large number of materials that show the characteristic of resistive switching. What's more, some researchers assert that all the materials have the characteristic. One of the most widely studied material is the transition metal oxide materials, which is easy to control, the fabricate process is simple and the mechanism of resistance change is clearer.At present, most of the researches focus on summarizing fabrication process, analyzing test data and discussing the resistive switching mechanism. However, simulation of the resistance change process is less. In these papers, most are about simulating the I-V hysteresis curve of RRAM by means of pure mathematical model, and only a few of them show the process of resistance by means of geometric modeling. The geometric modeling can reflect the dynamic resistance change process, which is helpful to comprehend the theory of conduction filament. Therefore, a more practicable simulation model is very important.In this paper, a new model of resistance variable memory is proposed, which is based on analyzing the advantages and disadvantages of the existing research models. In this model, the typical MIM structure is used to simulate the dynamic process of the formation and rupture of the oxygen vacancies conductive filament, by combining the current continuity equation, the Joule heating model and the oxygen vacancy transfer equation.In this paper, the Pt/Ti O2/Ti N structure RRAM based on the binery metal oxide was successfully simulated by using the COMSOL multiphysics software. By the process of set and reset, the moving of oxygen vacancies, with the coaction of electric field and temperature, is clearly reflected in the process of simulation. The simulation results show that the two-dimensional images can be explained qualitatively, and the one-dimensional linear maps can be analyzed quantitatively. And the internal cause of resistance variation is explained clearly from many aspects. At the same time, this paper also analyzes the influence of some parameters on the simulation results in the process of manufacturing, electrode material and test method. The result shows a good characteristic of resistive switching, and it's helpful for studying the physical mechanism.