Analysis Of Resistive Switching Mechanism Of Resistive Random Access Memory Based On Titanium Oxide

With the coming of information era, the nonvolatile memory(NVM) with large capacity, low power consumption and low cost properties, plays a more and more important role in the electronic market. However, the Flash NVM memory based on floating gate structure is gradually close to the physical limits. A new type NVM urgently needed to be developed. Resistive random access memory(RRAM) owing to its simple structure, compatibility with standard CMOS process and high density storge, become a contender to replace current Flash. At present, in the process of developing RRAM, a lot of questions needed to be solved, such as unclear resistive switching mechanism, poor devices stability and poor endurance. Our work focuses on the analysis of resistive switching mechanism of RRAM based on tantinium oxide. On this basis, the properties of RRAM were improved by structural optimization.Firstly, by changing the resistance switching Ti Ox layer, the properties of forming-free, low power and multilevel resistance switching were obtained in Al/Ti Ox/Cu device structure. The results of electrical meausurement confirmed the reason for explaining the multilevel resistance switching was the rupture of Cu conductive filaments(CFs) and oxygen vacancies(Vos) CFs. After the forming process, the relationship among electroforming-free, low power consumption and concentration of Cu in Ti Ox was cofirmed by depth profile Auger electron spectrometer.Secondly, the method of replacing the Al electrode by Pt electrode was designed in order to explore the formation sequence of Cu CFs and Vos CFs, and Cu/Ti Ox/Pt RRAM devices structure was obtained. The formation sequence of two different filaments was confirmed by the analysis of resistive switching mechanism of two resistance states in the set process.Thirdly, in order to improve the endurance and power properties of Cu/Ti Ox/Pt structure, a thin film Hf Ox was inserted between Cu electrode and Ti Ox resistive switching layer and Cu/Hf Ox/Ti Ox/Pt RRAM devices structure was obtained. The reason for the improvement of endurance and power consumption was that the Hf Ox thin film controled the region in which the rupture of Cu CFs occured and suppressed the formation of stronger Cu CFs.