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The relationship between low resistance (Ron) and cell size (from 40 nm to 100 \mu\m) is systematically investigated using a 1-Mb \Cux\Siy\O resistive RAM (RRAM) array. To our knowledge, this is the first study to attempt such an endeavor. Spacer pattern technology is employed to obtain a small cell size on the basis of a 0.13-\mu \m standard logic process. Ron exhibits minimal change at 100 \mu\m to 90 nm of RRAM size. However, it quadratically increases at 90 to 40 nm. The reset current, which is highly dependent on Ron, is linearly reduced fivefold in accordance with cell size, thereby improving overall power reduction and cell size scaling. The Ron dependence on cell size can be well explained by the dendritelike conductive filament model. [ABSTRACT FROM PUBLISHER]

The complex impedance spectroscopy method associated with capacitance–voltage is employed to investigate the resistive switching behavior of the bilayer structure for the first time. The reset current is reduced by more than one order for the \AlOx/\WOx bilayer compared with that of the single-layer structure. It is distinguished that each layer plays an important role. The \AlOx layer is the dominating switching layer, while the \WOx layer has the functions of controlling the conductive filaments in the \AlOx layer and acting as a series impedance to reduce the reset current. [ABSTRACT FROM AUTHOR]

Wide dispersions of memory switching parameters are observed in resistive random access memory based on AlJCux 0/Cu structure. Moreover, the switching instability in- duced by these dispersions is studied. In this letter, a ramped-pulse series operation method is put forward, which can improve switch- ing stability and cycling endurance remarkably. A method for minimizing the dispersion of Vreset by optimizing the amplitude of pulse is proposed further. The write-read-erase-read operations can be over 8 x 103 cycles without degradation by using the new operation mode. The role of Joule heating behind this behavior of AI/Cux O/Cu device is discussed. [ABSTRACT FROM AUTHOR]

Polycrystalline Cux O films produced by plasma oxidation are investigated for nonvolatile memory applications. Reversible bistable resistive switching from a high-resistance state to a low-resistance state, and vice versa, is observed in an integrated Al/Cux O/Cu structure under voltage sweeping. More than 3000 repetitive cycles are observed in 180-µm memory devices with an on/off ratio of ten times. Data testing shows that the devices meet the ten-year retention requirement for the storage of programmed logic signals. [ABSTRACT FROM AUTHOR]

The forming process, which is the first transition from fresh state to low resistance state, was investigated in CuxO memory films prepared by plasma-induced oxidation. X-ray photoelectron spectroscopy investigation of surface chemical bonds of CuxO films and Auger electron spectroscopy depth spectra show that the formation of a highly resistive CuO layer on the CuxO surface is the main reason for the requirement of a large forming voltage. After selectively deoxidizing the CuO into Cu2O, the need for the "forming" process disappears. [ABSTRACT FROM AUTHOR]