1,722,224 research outputs found
Communication-Hourglass-Shaped Metal-Filament Switching Device with Multi-Layer (AlOX/TiO2) Oxide Electrolytes
Get PDFThis paper proposes using hourglass-shaped metal filaments to improve the ON/OFF resistance ratio and retention characteristics of switching devices used in reconfigurable logic applications. These filaments are obtained by controlling the Cu-ion mobility in multi-layer oxide electrolytes. By adopting an upper AlOX and lower TiO2 electrolyte layers with respectively low and high Cu-ion mobility, we could form hourglass-shaped filaments as a result of suppressed Cu-ion injection and enhanced filament lateral growth. The hourglass-shaped metal filaments induced local Joule heating at the filament constriction, thus accelerating RESET operations. We confirmed that, as a result, Cu/AlOX/TiO2/W devices show high ON/OFF resistance ratios (>10(6)) and similar to 10-year retention properties at 80 degrees C. (C) The Author(s) 2016. Published by ECS. All rights reserved.110sciescopu
Communication-Impact of Filament Instability in an Ag2S-Based Conductive-Bridge RAM for Cross-Point Selector Applications
No full textWe show that the motion of Ag atoms in an Ag2S-based conductive bridge RAM system can be utilized for threshold-type selector applications. We found that the instability of an Ag filament could be increased in low current operation, where only few limited Ag ions are allowed to form a filament, and this resulting small filament enables the transition of a non-volatile memory system to a volatile mode. Furthermore, the enhanced activity of Ag atoms at elevated temperatures promotes the self-dissolution process when the bias is removed. As a result, threshold switching behavior with suppressed hysteresis can be achieved. (c) 2016 The Electrochemical Society. All rights reserved.1163sciescopu
Threshold switching behavior of Ag-Si based selector device and hydrogen doping effect on its characteristics
Get PDFThe effect of hydrogen treatment on the threshold switching property in a Ag/amorphous Si based programmable metallization cells was investigated for selector device applications. Using the Ag filament formed during motion of Ag ions, a steep-slope (5 mV/dec.) for threshold switching with higher selectivity (similar to 10(5)) could be achieved. Because of the faster diffusivity of Ag atoms, which are inside solid-electrolytes, the resulting Ag filament could easily be dissolved under low current regime, where the Ag filament possesses weak stability. We found that the dissolution process could be further enhanced by hydrogen treatment that facilitated the movement of the Ag atoms. (C) 2015 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).open11159sciescopu
Communication-Comprehensive Assessment of a Back-to-Back Schottky Diode with Ultrathin TiO2 Layer for Cross-Point Selector Applications
No full textA back-to-back Schottky diode configuration employing an ultrathin TiO2 layer has been assessed for application as a bi-polar selector in resistive random access memory by considering such factors as its working principle and scaling trends. Although higher rectification was achieved with an extremely low leakage current by the formation of a Schottky barrier, the maximum current remained low. This lower driving current can, however, be improved through engineering the properties of the TiO2 layer. Finally, the device characteristics of a scaled-down to similar to 30 nm were observed, the results of which strongly suggest that the device characteristics are governed by its whole area. (C) 2016 The Electrochemical Society. All rights reserved.1122sciescopu
Improved reset breakdown strength in a HfOx-based resistive memory by introducing RuOx oxygen diffusion barrier
Get PDFWe investigated the reset breakdown phenomenon of HfOx-based resistive memory for reliable switching operation in a fully CMOS compatible stack. Through the understanding on the effect of electrode materials and device area, our findings show that observed failure is attributed to additional oxygen vacancies close to the electrode interface, where switching is occurred. Therefore, RuOx serving as an oxygen diffusion barrier was introduced to suppress the generation of unwanted oxygen vacancies by preventing out-diffusion of oxygen through the electrode. As a result, significantly enhanced breakdown strength in HfOx/RuOx stack is achieved and resulting in improved cycle endurance with larger on/off ratio. (C) 2016 Author( s).1113Ysciescopu
Effect of nitrogen doping on variability of TaOx-RRAM for low-power 3-bit MLC applications
Get PDFThe switching uniformity and reliability of the TaOx based resistive random access memory (RRAM) device were investigated with varying nitrogen doping concentration. The nitrogen doped samples shows excellent electrical and reliability characteristics such as small switching variability for 3-bit multilevel per cell (MLC), low power operation and good retention properties. Compared with control sample, improved device characteristics of nitrogen doped device can be explained by nitrogen induced filament confinement. (C) The Author(s) 2015. Published by ECS.open117sciescopu
Linear stability of the Vlasov-Poisson system with boundary conditions
No full textWe study the linear stability of the Vlasov–Poisson system in one dimension on a finite interval and half line with the in-flow and specular reflection boundary conditions. Conditions for the existence and non-existence of stationary solutions are obtained. The behavior of the perturbed solutions is investigated in different contexts. We show that, if the equilibrium distribution μ is a strictly decreasing function of local energy density, then the Vlasov–Poisson system on a finite interval is stable in the (weighted) L2 sense for the in-flow and specular reflection boundary conditions. For the case μ is strictly increasing, we prove a similar result on a finite interval under some extra assumptions. Finally, in the last part of the article, the spectral stability of the Vlasov–Poisson system on an unbounded interval is studied with similar monotonicity assumptions on μ.111sciescopu
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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