• Title/Summary/Keyword: Chalcogenide memory

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A Study on the Switching Voltage of Memory Device using Amorphous Chalcogenide Semiconductor (비정질칼코게나이드반도체를 이용한 기억소자의 스위칭전압에 관한 연구)

  • 박창엽;정홍배
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.14 no.2
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    • pp.10-16
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    • 1977
  • Memory switching of the amorphous chalcogenide Ge-Te-Si memory devices were observed at various thicknesses and temperatures. For a given thickness, the distribution of threshold voltages shows a strong peaks, which is attributed to the intrinsic switching mechanism. The plot of Vth versus thickness indicates that threshold voltages were lowered and switching fields were raised as thickness was decreased. And threshold voltage sagged as temperature was raised and the fact that threshold voltage can be lowered at the temperature range under Tg was obtained.

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Electrolyte Mechanizm Study of Amorphous Ge-Se Materials for Memory Application (메모리 응용을 위한 비정질 Ge-Se 재료의 전해질 메카니즘 연구)

  • Nam, Ki-Hyun;Chung, Hong-Bay
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.06a
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    • pp.67-68
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    • 2009
  • In this study, we studied the nature of thin films formed by photodoping chalcogenide materials with for use in programmable metallization cell devices, a type of ReRAM. We investigated the resistance of Ag-doped chalcogenide thin films varied in the applied voltage bias direction from about $1\;M{\Omega}$ to several hundreds of $\Omega$. As a result of these resistance change effects, it was found that these effects agreed with PMC-RAM. The results imply that a Ag-rich phase separates owing to the reaction of Ag with free atoms from the chalcogenide materials.

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The PMC fabrication using the amorphous chalcogenide materials (비정질 칼코게나이드 재료를 이용한 PMC소자 제작)

  • Chung, Hong-Bay;Huh, Jung-Hwa;Son, Jung-Woo;Park, In-Ae;Cho, Dong-Hwan;Kim, Sung-Jin;Nam, Ki-Hyun
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.1262_1263
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    • 2009
  • Programmable Metallization Cell (PMC) is a memory device based on the electrolytical characteristic of chalcogenide materials. In this study, we investigate the nature of thin films formed by photo doping of Ag ions into chalcogenide materials for use in solid electrolyte of programmable metallization cell devices. We were able to do more economical approach by using copper which play an electrolyte ions role. The results imply that a Ag-rich phase separates owing to the reaction of Ag with free atoms from chalcogenide materials.

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A study for thermal and electrical properties of Ge-Se-Te Chalcogenide materials (Ge-Se-Te Chalcogenide 물질의 열적, 전기적 특성에 관한 연구)

  • Nam, Ki-Hyun;Park, Hyung-Kwan;Kim, Jae-Hoon;Koo, Sang-Mo;Chung, Hong-Bay
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.06a
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    • pp.33-34
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    • 2008
  • $Ge_1Se_1Te_2$ chalcogenide amorphous materials was prepared by the conventional melt-quenching method. Samples were prepared by e-beam evaporator system and thermal evaporator technique. The thermal properties were investigated in the temperature range 300K-400K and the electrical properties were studied in the voltage range from 0V to 3V below the corresponding glass trasition temperature. The obtained results agree with the electrothermal model for Phase-Change Random Access Memory.

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The Study on the Characteristic of Phase Transition in Differential Thickness of Se1Sb2Se2 Thin Films

  • Lee Jae-Min;Yang Sung-Jun;Shin Kyung;Chung Hong-Bay
    • Transactions on Electrical and Electronic Materials
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    • v.5 no.6
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    • pp.241-243
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    • 2004
  • The phase transition between amorphous and crystalline states in chalcogenide semiconductor films can be controlled by electrical or pulsed laser beam; hence some chalcogenide semiconductor films can be applied to electrically write/erase nonvolatile memory devices, where the low conductive amorphous state and the high conductive crystalline state are assigned to binary states. In this letter, the characteristics of phase transition in differential chalcogenide thin film are investigated. Al was used for the electrode as the thickness of 100, 300, 500 nm, respectively.

The Study of Phase-change with Temperature and Electric field in Chalcogenide Thin Film

  • Yang, Sung-Jun;Shin, Kyung;Park, Jung-Il;Lee, Ki-Nam;Chung, Hong-Bay
    • Transactions on Electrical and Electronic Materials
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    • v.4 no.5
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    • pp.24-27
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    • 2003
  • We have been investigated phase-change with temperature and electric field in chalcogenide Ge$_2$Sb$_2$Te$\sub$5/ thin film. T$\sub$c/(crystallization temperature) is confirmed by measuring the resistance with the varying temperature on the hotplate. We have measured I-V characteristics with Ge$_2$Sb$_2$Te$\sub$5/ chalcogenide thin film. It is compared with I-V characteristics after impress the variable pulse. The pulse has variable height and duration.

Properties on Annealing of Chalcogenide Materials at Programmable Metallization Cell (Programmable Metallization Cell에서 칼코게나이드 물질의 열처리에 따른 특성)

  • Choi, Hyuk;Kim, Hyun-Gu;Nam, Ki-Hyun;Ju, Long-Yun;Chung, Hong-Bay
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.11a
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    • pp.164-164
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    • 2007
  • Photodiffusion of silver into chalcogenide thin film is one of the most interesting effects that occurs in chalcogenide glass as it theatrically changes the properties of the initial material and forms a ternary. Programmable Metallization Cell(PMC) Randon Access Memory use for photodiffusion of mobile metal is based on the electrochemical growth and removal of nanoscale metallic pathway in thin film of solid electrolyte. This paper investigates the annling properties on Ag-doped $Ge_{25}Se_{75}$ thin film structure and describes the electrical characteristics of PMC-RAM. The composition of the intercalation products containing Ag is confirmed using X-ray diffraction which shows the formation of Ag-doped $Ge_{25}Se_{75}$.

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The phase transition with electric field in chalcogenide thin films (칼코게나이드 박막의 전기적 펄스에 의한 상변화 연구)

  • Yang, Sung-Jun;Shin, Kyoung;Lee, Jae-Min;Chung, Hong-Bay
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.05a
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    • pp.115-118
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    • 2004
  • The phase transition between amorphous and crystalline states in chalcogenide semiconductor films can controlled by electric pulses or pulsed laser beam; hence some chalcogenide semoconductor films can be applied to electrically write/erase nonvolatile memory devices, where the low conductive amorphous state and the high conductive crystalline stale are assigned to binary states. AST(AsSbTe) used to phase change material by applying electical pulses. Thickness of AST chalcogenide thin film have about 100nm. Electrodes are made of ITO and Al. $T_c$(Crystallization temperature) of AST system is lower than that of the GST(GeSbTe) system, so that the current pulse width of crystallization process can be decreased.

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Conductivity Characteristics of ${Ge_1}{Se_1}{Te_2}$ Amorphous Chalcogenide Thin Film for the Phase-Change Memory Application (상변화 메모리 응용을 위한 ${Ge_1}{Se_1}{Te_2}$ 비정질 칼코게나이드 박막의 전도 록성)

  • Choi, Hyuk;Kim, Hyun-Gu;Cho, Won-Ju;Chung, Hong-Bay
    • Proceedings of the KIEE Conference
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    • 2006.10a
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    • pp.32-33
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    • 2006
  • As next generation nonvolatile memory, chalcogenide-based phase change memory can substitute for a conventional flash memory from its high performance. Also, fast writing speed, low writing voltage, high sensing margin, low power consumption and repetition reliability over $10^{15}$ cycle shows its possibility. At our laboratory, we invented ${Ge_1}{Se_1}{Te_2}$ material to alternate with conventional ${Ge_2}{Sb_2}{Te_5}$ for improve its ability. We respect the ${Ge_1}{Se_1}{Te_2}$ material can be a solution for high power consumption problem and long time at 'set' performance. A conductivity experiment from variable temperature was performed to see reliability of repetition at read and write performance. Compare with conventional ${Ge_2}{Sb_2}{Te_5}$ material, these two materials are used as complex compound to get the finest parameter.

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The physical properties and switching characteristics of amorphous $Ge_2Sb_2Te_5$ thin film (비정질 $Ge_2Sb_2Te_5$ 박막의 물리적 성질 및 스위칭 특성)

  • Lee, Jae-Min;Yang, Sung-Jun;Shin, Kyung;Chung, Hong-Bay
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.11a
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    • pp.268-271
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    • 2004
  • The phase transition from amorphous to crystalline states, and vice versa, of $Ge_2Sb_2Te_5$ films by applying electrical pulses have been studied. This material can be used as nonvolatile memory. The reversible phase transition between the amorphous and crystalline states, which is accompanied by a considerable change in electrical resistivity, is exploited as means to store bits of information. The nonvolatile memory cells are composed of a simple sandwich (metal/chalcogenide/metal). It was formed that the threshold voltage depends on thickness, electrode distance, annealing time and temperature, respectively.

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