• Title/Summary/Keyword: memory switching

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Formation of Threshold Switching Chalcogenide for Phase Change Switch Applications

  • Bang, Ki Su;Lee, Seung-Yun
    • Applied Science and Convergence Technology
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    • v.23 no.1
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    • pp.34-39
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    • 2014
  • The programmable switches which control the delivery of electrical signals in programmable logic devices are fabricated using memory technology. Although phase change memory (PCM) technology is one of the most promising candidates for the manufacturing of the programmable switches, the threshold switching material should be added to a PCM cell for realization of the programmable switches based on PCM technology. In this work, we report the impurity-doped $Ge_2Sb_2Te_5$ (GST) chalcogenide alloy exhibiting threshold switching property. Unlike the GST thin film, the doped GST thin film prepared by the incorporation of In and P into GST is not crystallized even at the postannealing temperature higher than $200^{\circ}C$. This specific crystallization behavior in the doped GST thin film is attributed to the stabilization of the amorphous phase of GST by In and P doping.

Memristive Devices Based on RGO Nano-sheet Nanocomposites with an Embedded GQD Layer (저결함 그래핀 양자점 구조를 갖는 RGO 나노 복합체 기반의 저항성 메모리 특성)

  • Kim, Yongwoo;Hwang, Sung Won
    • Journal of the Semiconductor & Display Technology
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    • v.20 no.1
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    • pp.54-58
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    • 2021
  • The RGO with controllable oxygen functional groups is a novel material as the active layer of resistive switching memory through a reduction process. We designed a nanoscale conductive channel induced by local oxygen ion diffusion in an Au / RGO+GQD / Al resistive switching memory structure. A strong electric field was locally generated around the Al metal channel generated in BIL, and the local formation of a direct conductive low-dimensional channel in the complex RGO graphene quantum dot region was confirmed. The resistive memory design of the complex RGO graphene quantum dot structure can be applied as an effective structure for charge transport, and it has been shown that the resistive switching mechanism based on the movement of oxygen and metal ions is a fundamental alternative to understanding and application of next-generation intelligent semiconductor systems.

The Characteristics of Conduction rind Switching Voltage for As-Ge-Te Memory Switching Device (As-Ge-Te 메모리 스위칭 소자의 전도 및 스위칭 전압 특성)

  • 이병석;이현용;이영종;정흥배
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1995.11a
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    • pp.67-70
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    • 1995
  • Amorpous As$\sub$10/Ge$\sub$15/Te$\sub$75/ device shows the memory switching characterisite under d.c. bias. In bulk material, a-As$\sub$10/Ge/sub15/Te$\sub$75/s switching voltage range is above 100 volts. Our purposes in this gaudy are decreasing a switching threshold voltage, finding the properties of d.c., a.c. conduction, and the characterisitics of switching threshold voltage fur a-As$\sub$10/Ge$\sub$15/Te$\sub$75/. As the results, the d.c.and a.c. conductivities increase with temperature. From the data of conductivity, various electrical and physical properties are obtained experimentally. The switching threshold voltages decrease with increasing annealing temperature and time, but increase with increasing film thickness and distance of electrode for d.c. bias.

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The characteristics of D.C. switching threshold voltage for amorphous $As_{10}Ge_{15}Te_{75}$ thin film (비정질 $As_{10}Ge_{15}Te_{75}$박막의 D.C. 스위칭 임계전압 특성)

  • 이병석;이현용;이영종;정홍배
    • Electrical & Electronic Materials
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    • v.9 no.8
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    • pp.813-818
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    • 1996
  • Amorphous As$_{10}$Ge$_{15}$ Te$_{75}$ device shows the memory switching characteristics under d.c. bias. In bulk material, a-As$_{10}$Ge$_{15}$ Te$_{75}$ switching threshold voltage (V$_{th}$) is very high (above 100 volts), but in the case of thin film, V$_{th}$ decreases to a few or ten a few volts. The characteristics of V$_{th}$ depends on the physical dimensions such as the thickness of thin film and the separation between d.c. electrodes, and the annealing conditions. The switching threshold voltage decreases exponentially with increasing annealing temperature and annealing time, but increases linearly with the thickness of thin film and exponentially with increasing the separation between d.c. electrodes. The desirable low switching threshold voltage, therefore, can be obtained by the stabilization through annealing and changing physical dimensions.imensions.sions.

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Electrical Conduction and Resistance Switching Mechanisms of Ag/ZnO/Ti Structure

  • Nguyen, Trung Do;Pham, Kim Ngoc;Tran, Vinh Cao;TuanNguyen, Duy Anh;Phan, Bach Thang
    • Journal of IKEEE
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    • v.17 no.3
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    • pp.229-233
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    • 2013
  • We investigated electrical conduction and resistance switching behavior of the Ag/ZnO/Ti structures for random access memory devices. These films were prepared on glass substrate by dc sputtering technique at room temperature. The resistance switching follows unipolar switching mode with small switching voltages (0.4 V - 0.6 V). Two electrical conduction mechanisms dominating the LRS and HRS are Ohmic and trap-controlled space charge limited current, respectively. These both conductions are consistent with the filamentary model. Based on the filamentary model, the switching mechanism was also interpreted.

Construction Methods of Switching Network for a Small and a Large Capacity AMT Switching System (소용량 및 대용량의 ATM시스템에 적합한 스위칭 망의 구성 방안)

  • Yang, Chung-Ryeol;Kim, Jin-Tae
    • The Transactions of the Korea Information Processing Society
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    • v.3 no.4
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    • pp.947-960
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    • 1996
  • The primary goal for developing high performance ATM switching systems is to minimized the probability of cell loss, cell delay and deterioration of throughput. ATM switching element that is the most suitable for this purpose is the shared buffer memory switch executed by common random access memory and control logic. Since it is difficult to manufacture VLIS(Very Large Scale Integrated circuit) as the number of input ports increased, the used of switching module method the realizes 32$\times$32, 150 Mb/s switch utilizing 8$\times$8, 600Mb/s os 16$\times$16, 150Mb/s unit switch is latest ATM switching technology for small and large scale. In this paper, buffer capacity satisfying total-memory-reduction effect by buffer sharing in a shared buffer memory switch are analytically evalu ated and simulated by computer with cell loss level at traffic conditions, and also features of switching network utilizing the switching module methods in small and large-capacity ATM switching system is analized. Based on this results, the structure in outline of 32$\times$32(4.9Gb/s throughput), 150Mb/s switches under research in many countries is proposed, and eventually, switching-network structure for ATM switching system of small and large and capacity satisfying with above primary goals is suggested.

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Graphene Oxide Thin Films for Nonvolatile Memory Applications

  • Kim, Jong-Yun;Jeong, Hu-Young;Choi, Hong-Kyw;Yoon, Tae-Hyun;Choi, Sung-Yool
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.02a
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    • pp.9-9
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    • 2011
  • There has been strong demand for novel nonvolatile memory technology for low-cost, large-area, and low-power flexible electronics applications. Resistive memories based on metal oxide thin films have been extensively studied for application as next-generation nonvolatile memory devices. However, although the metal oxide-based resistive memories have several advantages, such as good scalability, low-power consumption, and fast switching speed, their application to large-area flexible substrates has been limited due to their material characteristics and necessity of a high-temperature fabrication process. As a promising nonvolatile memory technology for large-area flexible applications, we present a graphene oxide-based memory that can be easily fabricated using a room temperature spin-casting method on flexible substrates and has reliable memory performance in terms of retention and endurance. The microscopic origin of the bipolar resistive switching behaviour was elucidated and is attributed to rupture and formation of conducting filaments at the top amorphous interface layer formed between the graphene oxide film and the top Al metal electrode, via high-resolution transmission electron microscopy and in situ x-ray photoemission spectroscopy. This work provides an important step for developing understanding of the fundamental physics of bipolar resistive switching in graphene oxide films, for the application to future flexible electronics.

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memory and Switching Diodes of As Te Ge Amorphous Semiconductor (As Te Ge 무정형 반도체의 기억 및 스위칭소자)

  • 박창엽
    • 전기의세계
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    • v.22 no.2
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    • pp.45-50
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    • 1973
  • Amorphous semiconducting diodes from As Te Ge systm of which resitivity are 10$^{6}$ -10$^{8}$ .ohm.-cm order, are made and they exhibited several conducting states. A high conductivity, low conductivity and memory state are reported. Temperature dependency of the specimens are widerange. According to the procedure and cooling method, specimens are made easily or not. Threshold voltage of switching and memory diodes is in proportional to compositonal quantity of Arsenic. Threshold voltage is changed widely according to ambient temperature. Threshold voltage of #132 is 620V at 25.deg. C, 70V at 100.deg. C.

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Resistive Switching Memory Devices Based on Layer-by-Layer Assembled-Superparamagnetic Nanocomposite Multilayers via Nucleophilic Substitution Reaction in Nonpolar Solvent

  • Kim, Yeong-Hun;Go, Yong-Min;Gu, Bon-Gi;Jo, Jin-Han
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2011.05a
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    • pp.243.1-243.1
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    • 2011
  • We demonstrate a facile and robust layer-by-layer (LbL) assembly method for the fabrication of nonvolatile resistive switching memory (NRSM) devices based on superparamagnetic nanocomposite multilayers, which allows the highly enhanced magnetic and resistive switching memory properties as well as the dense and homogeneous adsorption of nanoparticles, via nucleophilic substitution reaction (NSR) in nonpolar solvent. Superparamagnetic iron oxide nanoparticles (MP) of about size 12 nm (or 7 nm) synthesized with oleic acid (OA) in nonpolar solvent could be converted into 2-bromo-2-methylpropionic acid (BMPA)-stabilized iron oxide nanoparticles (BMPA-MP) by stabilizer exchange without change of solvent polarity. In addition, bromo groups of BMPA-MP could be connected with highly branched amine groups of poly (amidoamine) dendrimer (PAMA) in ethanol by NSR of between bromo and amine groups. Based on these results, nanocomposite multilayers using LbL assembly could be fabricated in nonpolar solvent by NSR of between BMPA-MP and PAMA without any additional phase transfer of MP for conventional LbL assembly. These resulting superparamagnetic multilayers displayed highly improved magnetic and resistive switching memory properties in comparison with those of multilayers based on water-dispersible MP. Furthermore, NRSM devices, which were fabricated by LbL assembly method under atmospheric conditions, exhibited the outstanding performances such as long-term stability, fast switching speed and high ON/OFF ratio comparable to that of conventional inorganic NRSM devices produced by vacuum deposition.

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Design of Switching Fabric Supporting Variable Length Packets (가변 길이 패킷을 지원하는 스위칭 패브릭의 설계)

  • Ryu, Kyoung-Sook;Kim, Mu-Sung;Choe, Byeong-Seog
    • Journal of KIISE:Computing Practices and Letters
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    • v.14 no.3
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    • pp.311-315
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    • 2008
  • The switching fabric used to make high speed switching for packet transfer between input and output interface in recent internet environments. Without making any changes in order to remain ATM switching fabric, the existing structures should split/reassemble a packet to certain size, set aside cross-point buffer and will put loads on the system. In this paper, we proposed a new switch architecture, which has separated data memory plane and switching plane packet data will be stored on the separate memory structure and simultaneously only the part of the memory address pointers can pass the switching fabric. The small mini packets which have address pointer and basic information would be passed through the switching fabric. It is possible to achieve the remarkable switching performance than other switch fabrics with contending variable length packets.