Resistive switching memory, flexible electronics equipment, and graphene-oxide-based devices have attracted much attention recently because of their possible application in next-generation electronic devices. In this study, a graphene-oxide-based flexible resistive switching memory is proposed. The flexibility and nonvolatility of the flexible device are demonstrated. A possible resistive switching filamentary model of the flexible device is also proposed. The experimental results indicate that the proposed graphene-oxide-based device is promising for use in next-generation nonvolatile memory and flexible electronics equipment.
We found CuOx thin film with gradual oxygen concentration (GOC) distribution enhances resistive switching characteristics for nonvolatile memory applications. Using Al/ GOC CuOx /Cu structure, not only no forming is needed, also the endurance of switching is greatly enhanced. The device with GOC CuOx demonstrates resistance on/off ratio greater than 100, and endurance of more than 12000 cycles. A ramped pulses series (RPS) operation method is also put forward, which can improve switching stability and cycling endurance remarkably. A method for minimizing the dispersion of Vreset by optimizing amplitude of pulse is proposed further. Dispersion of Vreset can be minimized by using optimized Vstart of RPS. And this phenomenon agrees well with the Joule heating model that the RESET process of memory switching is associated with rupturing of filaments by Joule heating.Introduction The Binary oxide-based resistive random access memory (RRAM)1 has attracted growing interest as one of the most promising alternatives for easing challenges of flash scaling down, owing to its good scalability and ease of fabrication 1-3 . But several issues have to be solved for practical application, including instability of operation, endurance, data retention, integration etc. CuxO based RRAM has high affinity with standard logic process. The good resistive switching characteristics of Cu x O has been reported, where the maximum reported endurance of Cu x O-based RRAM cell is about 1000 cycles 4-5 .In this work, we report that the copper oxide based RRAM cell can achieve cycling up to 12000 cycles as well as no initial "forming process" needed. This "forming-free" characteristic of device appears related to thinner CuO cap layer with saturated oxygen; and the endurance enhancement appears related to the profile and magnitude of oxygen vacancies in CuxO 6-7 . Meanwhile, stable switching characteristics and narrow distribution of resistive switching parameters are improved.
ExperimentThe device (Al/ GOC CuOx/Cu) can be prepared by electro-chemical plating (ECP) surface treatment by plasma reactive ionic etch (RIE), and oxidation by inductively coupled plasma (ICP) or thermal process. Cu film with the thickness of 1 m µ was deposited on Ta/TaN/SiO2/Si substrate with standard Novellus® ECP system at room temperature. After Cu film was deposited, the surface is slightly etched (for removing native Cu oxide on surface) by RIE and then plasma oxidized in ICP chamber. The rest of Cu layer acts as the bottom electrode. 180 × 180µm Al top electrodes with the thickness of 400 nm were fabricated by evaporation and lift off process. Keithley 4200-SCS
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.