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Resistive switching memory (RRAM) features many optimal properties for future memory applications that make RRAM a strong candidate for storage-class memory and embedded nonvolatile memory. This paper addresses the cycling-induced degradation of RRAM devices based on a HfO2 switching layer. We show that the cycling degradation results in the decrease of several RRAM parameters, such as the resistance of the low-resistance state, the set voltage V\mathrm{ set} , the reset voltage V\mathrm{ reset} , and others. The degradation with cycling is further attributed to enhanced ion mobility due to defect generation within the active filament area in the RRAM device. A distributed-energy model is developed to simulate the degradation kinetics and support our physical interpretation. This paper provides an efficient methodology to predict device degradation after any arbitrary number of cycles and allows for wear leveling in memory array. [ABSTRACT FROM AUTHOR]

In the study of resistive random access memory using GeTeOx film as the switching layer, the device performed excellent property of bipolar resistive switching (BRS), which could be gradually transformed to the complementary resistive switching (CRS) by varying SET process current compliance. The conductive filament conduction mechanism of BRS could be verified by electrical characteristics and reliable data fitting. Through increasing current compliance of the SET process, CRS could be achieved due to higher activity of oxygen vacancies originated from the intensified thermal effect. This paper was beneficial to understand the switching mechanisms of BRS and CRS and provide a method to realize interconversion. Moreover, it was also a potential and promising device to be applied in the neurosynaptic biomimetic field. [ABSTRACT FROM AUTHOR]

In this paper, indium-tin-oxide (ITO) was used to act as both insulator and top electrode in resistive random access memory (RRAM) on identical bottom substrates. This is achieved by cosputtering an ITO target with nitride (N2) or oxygen (O2) gas as the insulator; then capping by an ITO electrode, such that both the rectifier and RRAM characteristics can be achieved before and after a forming process, respectively. In contrast, using pure ITO as an insulator does not exhibit RRAM behavior. To verify the rectifier and RRAM characteristics, material analyses and electrical measurements at various temperatures were conducted. Reliability tests including retention and endurance were also applied to verify the resistance switching stability. Finally, the rectifier and RRAM conduction models were proposed to examine the resistance switching behaviors. By applying the ITO material as both electrode and insulator, the resistance switching characteristic with high reliability is thus obtained. [ABSTRACT FROM AUTHOR]

There has been a strong demand for developing an ultradense and low-power nonvolatile memory technology. In this paper, we present a carbon-based resistive random access memory device with a carbon nanotube (CNT) electrode. An amorphous carbon layer is sandwiched between the fast-diffusing top metal electrode and the bottom CNT electrode, exhibiting a bipolar switching behavior. The use of the CNT electrode can substantially reduce the size of the active device area. We also demonstrate a carbon-based complementary resistive switch (CRS) consisting of two back-to-back connected memory cells, providing a route to reduce the sneak current in the cross-point memory. The bit information of the CRS cell is stored in a high-resistance state, thus reducing the power consumption of the CRS memory cell. This paper provides valuable early data on the effect of electrode size scaling down to nanometer size. [ABSTRACT FROM PUBLISHER]

A highly transparent resistive random access memory with a configuration of multilayer graphene (MLG)/ Dy2O3 /indium tin oxide (ITO) structure is demonstrated in this paper. The fabricated device is transparent, with 80% transmittance at 550 nm. The MLG/ Dy2O3 /ITO device shows unipolar resistance switching with a low operation current (<100~\muA) , low operation voltage (<1~V) , low power consumption (<100~\muW) , high resistance ratio (>10^4) , fast switching speed (<60~ns) , reliable data retention, and promising cycle endurance properties (>200~cycles) , which makes a step toward the realization of low-power transparent electronics for next-generation nonvolatile memory application. The MLG/ Dy2O3 /ITO device exhibited typical filamentary-conduction-type resistive random access memory behavior and no forming process is required. High resistance state (HRS) increases with a reduced device area while low resistance state (LRS) is insensitive to the device sizes. Moreover, Raman spectra obtained in pristine state, HRS, and LRS indicate that the lower power consumption of MLG/ Dy2O3 /ITO device is attributable to the formation of oxygen graphene layers. [ABSTRACT FROM AUTHOR]

Resistive switching memory (RRAM) devices generally rely on the formation/dissolution of conductive filaments through insulating materials, such as metal oxides and chalcogenide glasses. Understanding the mechanisms for filament formation and disruption in resistive switching materials is a critical step toward the development of reliable and controllable RRAM for future-generation storage. In particular, the capability to control the filament resistance and the reset current through the compliance current during filament formation may provide a key signature to clarify the switching mechanism. This paper provides a physically based explanation for the universal resistance switching in bipolar RRAM devices. A numerical model of filament growth based on thermally activated ion migration accounts for the resistance switching characteristics. The same physical picture is extended to numerically model the reset transition. The impact of migration parameters and experimental setup on the set/reset characteristics is discussed through numerical simulations. [ABSTRACT FROM AUTHOR]