• Title/Summary/Keyword: Chalcogenide

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The Solid-electrolyte Characteristics of Ag-doped Germanium Selenide for Manufacturing of Programmable Metallization Cell (Programmable Metallization Cell 제작을 위한 Ag-doped Germanium Selenide의 고체전해질 특성)

  • Nam, Ki-Hyun;Koo, Sang-Mo;Chung, Hong-Bay
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.11a
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    • pp.86-87
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    • 2008
  • 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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Electrical Switching Characteristics of Thin Film Transistor with Amorphous Chalcogenide Channel

  • Nam, Gi-Hyeon;Kim, Jang-Han;Jeong, Hong-Bae
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.08a
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    • pp.280-281
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    • 2011
  • We fabricated the devices of TFT type with the amorphous chalcogenide channel. A single device consists of a Pt source and drain, a Ti glue layer and a GeSe chalcogenide channel layer on SiO2/Si substrate which worked as the gate. We confirmed the drain current with variations of gate bias and channel size. The I-V curves of the switching device are shown in Fig. 1. The channel of the device always contains amorphous state, but can be programmed into two states with different threshold voltages (Vth). In each state, the device shows a normal Ovonic switching behavior. Below Vth (OFF state), the current is low, but once the biasing voltage is greater than Vth (ON state), the current increases dramatically and the ON-OFF ratio is about 4 order. Based on the experiments, we contained the conclusion that the gate voltage can enhance the drain current, and the electric field by the drain voltage affects the amorphous-amorphous transition. The switching device always contains the amorphous state and never exhibits the Ohmic behavior of the crystalline state.

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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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Evaluation of Thermography Camera Using Molded Optical Lens for Medical Applications (몰드성형 광학렌즈를 이용한 의료기기용 열화상카메라 체열진단의 적용도 평가)

  • Ryu, Seong Mi;Kim, Hye-Jeong
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.26 no.8
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    • pp.624-628
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    • 2013
  • With the recent development of less-costly uncooled detector technology, expensive optics are among the remaining significant cost drivers in the thermography camera. As a potential solution to this problem, the fabrication of IR lenses using chalcogenide glass has been studied in recent years. We report on the molding and evaluation of a ultra-precision chalcogenide-glass lens for the thermography camera for body-temperature monitoring. In addition, we fabricated prototype thermography camera using the chalcogenide-glass lens and obtained the thermal image from the camera. In this work, it was found out that thermography camera discerned body-temperature between 20 and $50^{\circ}C$ through the analysis of thermal image. It is confirmed that thermography camera using the chalcogenide-glass lens is applicable to the body-temperature monitoring system.

Effects of Chalcogenide Glasses Thin Film Encapsulation Layer on Lifetime of Organic Light Emitting Diodes

  • Fanghui, Zhang;Jianfei, Xi
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.839-842
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    • 2009
  • In this paper, chalcogenide glasses material(Se, Te, Sb) is firstly used as encapsulation layer of OLEDs under high vacuum of $10^{-4}$Pa. In the experiments, properties of OLEDs encapsulated by Se, Te, Sb thin film is compared with that of device encapsulated by traditional method. It is found that Se, Te, Sb film can extend lifetime of devices to 1.4, 2, 1.3 times respectively. Chalcogenide glasses film as encapsulation layer has little effect on some characteristics of device. The research indicated that OLEDs can be well protected upon applying Se, Te, Sb film as encapsulation layer. It is clear that it can prolong the lifetime obviously.

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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.

Annealing Effect of the Chalcogenide Thin Film for Holographic Grating Formation (홀로그래픽 격자 형성에 대한 칼코게나이드 박막의 열처리 효과)

  • Park, Jung-Il;Shin, Kyung;Lee, Jung-Tae;Lee, Young-Jong;Chung, Hong-Bay
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.16 no.8
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    • pp.736-739
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    • 2003
  • We prepared the chalcogenide As$\_$40/Ge$\_$10/Se$\_$15/S$\_$35/, Se$\_$75/Ge$\_$25/ thin film. Holographic grating was formed by the He-Ne laser( λ =633 nm). Annealing at 100$^{\circ}C$ and 200$^{\circ}C$ has been used to change the optical property of chalcogenide thin films for holographic grating formation. As the results, large variation of the optical property was generated at the As$\_$40/Ge$\_$10/Se$\_$15/S$\_$35/ chalcogenide film. Diffraction efficiency of the As$\_$40/Ge$\_$10/Se$\_$15/S$\_$35/ film has been enhanced about three times

A study on physical and chemical properties of chalcogenides for an aspheric lens (비구면 렌즈의 설계 및 제조를 위한 칼코게나이드계 유리의 물리적 화학적 특성 연구)

  • Ko, Jun-Bin;Kim, Jeong-Ho
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.19 no.3
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    • pp.388-393
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    • 2010
  • In recent years the research has been focused on the preparation of special glasses, i.e., chalcogenide and heavy metal oxide ones that can transmit optical radiation above 2 um and also other optical parameters exceed those of silica based glasses. The attention in this paper is focused on chalcogenide glasses, on preparation of high quality base glass, for an application in infrared optical product design and manufacture. The amorphous materials of As-Se and Ge-As-Se chalcogenides were prepared by a standard melt-quenching technique. The compositions were mesaured by ICP-AES and EPMA, and structural and thermal properties were studied through various annealing processes. Several anomalies of glass transition and crystallization were observed in the DSC/DTA/TG results of the chalcogenide glass.

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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