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The statistics of the RESET voltage (VRESET) and the RESET current (IRESET) of Pt/HfO2/Pt resistive random access memory (RRAM) devices operated under unipolar mode are analyzed. The experimental results show that both the distributions of IRESET and VRESET are strongly influenced by the distribution of initial resistance in the ON state (RON), which is related to the size of the conductive filament (CF) before RESET. By screening the statistical data into different resistance ranges, both the distributions of IRESET and VRESET are shown to be compatible with a Weibull model. Contrary to previous reports for NiO-based RRAM, the Weibull slopes of the IRESET and VRESET are demonstrated to be independent of RON. This is an indication that the RESET point, defined in this letter as the point of maximum current, corresponds to the initial phase of CF dissolution. On the other hand, given that the scale factor of the VRESET distribution (VRESET63\%) is roughly independent of RON, the scale factor of the IRESET (IRESET63\%) is inversely proportional to RON. This is analogous to what was found in NiO-based RRAM and it is consistent with the thermal dissolution model of RESET. Our results highlight the intrinsic link between the SET and RESET statistics and the need for controlling the variation of ON-state resistance to reduce the variability of the RESET voltage and current. [ABSTRACT FROM PUBLISHER]

NiO-based resistive-switching memory (RRAM) is a promising new technology for high-density nonvolatile storage. The main obstacles to practical application are the large and hardly scalable reset (programming) current and the reliability at high temperature. This letter studies temperature-accelerated data retention in RRAM cells from both experimental and theoretical standpoints, addressing the size/nature of the conductive filament and clarifying the tradeoff between data retention and reset current. [ABSTRACT FROM AUTHOR]

This letter addresses the impact of electrode materials on programming characteristics of NiO-based resistive-switching memory devices. The use of noble metals for the electrodes, instead of Si contacts, is shown to result in a lowering of the set/reset voltage. This is ascribed to a different chemical composition of the conductive filament (CF) in the set state for varying electrodes, suggesting that atomic diffusion from the electrodes takes place during the formation of the CF at the set process. The results are interpreted on the basis of numerical simulations of the reset transition, which are compared with experimental data. [ABSTRACT FROM AUTHOR]