The Study And Optimization Of Endurance Of TiO_x-Based Resistive Random Access Memory

With the development of science and technology, and popularity of portable devices and the Moore Law, we are drived to study the memory with low power、high integration and fast speed of read and write. Additionally, thanks to the contrary between the leakage current and the integration in the existing Flash, the Flash comes to the technology node, indicating the end of the charge-memory. Based on this background, resistive random access memory(RRAM), as the new generation of nonvolatile memory, had emerges, and attracted lots of attentions of the researchers. However, with the short time of the research, there are still many questions, such as the unclear resistance switching(RS) mechanism, the bad uniformity of the high resistance state(HRS) and the low resistance state(LRS), and the Endurance degradation.Accordingly, we study Ti Ox for the above questions. In this paper, we prepared the Al、Cu、Ti N/Ti Ox/Pt structures by magnetron sputtering and electron beam evaporation. And we tested the I-V characteristics using B1500 A and Lake Shore 325 Temperature Controller.Firstly, we induced different RS mechanisms using the different top electrodes. In this, Ti N and Cu could induce filament mechanism; Al could induce the Space Charge Limited Current(SCLC) mechanism. Then we compared their Endurance, and taked the uniformity of HRS and LRS as standard, we could find that Electronic Switching(ES) was superior to Ionic Switching(IS) and Ti N structure was superior to Cu structure, they might be related with the extent of damages of particles movement during RS.In this process, we could notice that the different top electrodes made the different interface contact by the different work function and chemical reaction, and the interface contact could induce IS and ES mechanisms by the different hinder effects of injected electrons.Secondly, we studied the Endurance degradation mechanism of Al structure with the help of SCLC mechanism and I-V fitting. And the degradation ascribed to the decrease of the traps, and then we conformed the traps were mainly filled with electrons by testing the relationship between the HRS degradation ratio and the Vset、Vreset. Based on the above study, we optimize the Endurance by using Vforming of different polarities and using different electrodes.In summary, the paper studied the effects of top electrodes on Ti Ox-RRAM and compared their Endurance. And we studied the Endurance degradation mechanism of Al structure. The study will drive the study and industrialization of Ti Ox-RRAM..