• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1285-1286
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• 2008

A detailed investigation and structure of tested samples are clearly presented. As a reference, $Ge_1Se_1Te_2/As$ only sample was also investigated. We used compound of Ge-Se-Te material for phase-change cell. Actually, the performance properties have been improved surprisingly then conventional Ge-Sb-Te. However, crystallization time was as long as ever for amorphization time. We conducted this experiment in order to solve that problem by doping-As with Ag layer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.234-237
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• 1996

The amorphous chalogenide semiconductors are new material in semiconductor physics. Their properties, especially electronic and optical properties are main motives for device application. Amorphous As$_{10}$Ge$_{15}$ Te$_{75}$material has the stable ac conductivity at high frequency and the dc memory switching property. At higher frequency than 10MHz, ac conductivity of As$_{10}$Ge$_{15}$ Te$_{75}$ thin film is much higher than below frequency and independent of temperature and frequency. If the dc voltages are applied between edges of thin film, one can see the dc memory switching phenomenon, in other words the dc conductivity increases quite a few of magnitude after the threshold voltage is applied. Using the stable ac conductivity at high frequency and the increase of conductivity after dc memory switching, As$_{10}$Ge$_{15}$ Te$_{75}$thin film is considered as new material for microwave switch devices.vices.es.vices.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.103-103
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• 2009

본 논문에서는 기존의 GST(GeSbTe=2:2:5)와 비교하여 상변화 재료로서의 Ga 도핑된 $Ge_2Sb_2Te_5$의 가능성을 확인하고자 하였다. 실험에 사용된 Ga 도핑된 $Ge_2Sb_2Te_5$ 박막은 전통적 melt-quenching 방법에 의해 비정질로 제작된 벌크를 Thermal evaporation을 통하여 Si(100) 및 유리 (coming glass, 7059) 기판 위에 200nm의 두께로 증착하여 제작하였다. 각 박막의 상변화 특성은 여러 온도에서 열처리된 박막을 X-ray diffraction (XRD) 측정을 통하여 확인하였다. 각 조성 박막의 비정질-결정질 상변화속도 비교를 위하여 나노-펄스 스캐너 (nano-pulse scanner)를 사용하여 power; 1~17mW, pulse duration; 10~460ns 범위에서 박막의 상변화에 따른 반사도 차이를 측정 분석하였다. Ga의 도핑농도에 따른 전기적 특성 차이를 확인하기 위하여 4-point probe를 이용하여 박막의 면 저항을 측정하였고 또한 hall 측정을 통하여 박막의 흘 계수, 흘 농도 및 이동도를 확인하고 Ga가 상전이에 미치는 영향에 대하여 분석하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.191-192
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• 2008

For phase transition method, good record sensitivity, low heat radiation, fast crystallization and hi-resolution are essential. Also, a retention time is very important part for phase-transition. In our past papers, we chose composition of $Ge_1Se_1Te_2$ material to use a Se factor which has good optical sensitivity than conventional Sb. Ge-Se-Te and Ag/$Ge_1Se_1Te_2$ samples are fabricated and irradiated with He-Ne laser and DPSS laser to investigate a reversible phase change by light. Because of Ag ions, the Ag layer inserted sample showed better performance than conventional one. We should note that this novel one showed another possibility for phase-change random access memory.

• 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.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.229-231
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• 1996

We are studied the stability of amorphous and crystalline $Te_{100-x}Ge_x$ (x=10, 15. 25, 40, 50, 60 at.%) thin films by observing the degradation in 8O%RH/$66^{\circ}C$ environment and the reflectance ratio. The degradation was observed with the transmittance and reflectance, the reflectance was measured at 780nm in the wavelength range of diode laser. In amorphous $Te_{100-x}Ge_x$ thin films of below x=4O at.%, the degradation was observed, the thin film of x=10 at.% was shown the degradation degree of 12.5%. In crystalline $Te_{100-x}Ge_x$ thin films of x=10, 40 at.%, the degradation degree were 12.8%, 13%, respectively. The reflectance ratio were shown above 20% in. all composition ratio. Therefore, we are expected that $Te_{100-x}Ge_x$ thin films of x=50, 60 at.% has the long life for the optical recording media.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.154-155
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• 2007

PRAM(Phase-Change RAM) is a promising memory that can solve the problem of conventional memory and has the nearly ideal memory characteristics. We reviewed the issues for high density PRAM integration. Writing current reduction is the most urgent problem for high density PRAM realization. So, we studied new constitution of $Ge_1Se_1Te_2$ chalcogenide material and presented the method of reducing the contact size between $Ge_1Se_1Te_2$ and electrode. A small-contact-area electrode is used primarily to supply current into and minimize heat loss from the chalcogenide. In this letter, we expect the method of reducing the contact size between $Ge_1Se_1Te_2$ and electrode to decrease writing current.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.15-16
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• 2005

Chalcogenide phase change memory has high performance to be next generation memory, because it is a nonvolatile memory processing high programming speed, low programming voltage, high sensing margin, low consumption and long cycle duration. We have developed a new material of PRAM with $Ge_1Se_1Te_2$. This material has been propose to solve the high energy consumption and high programming current. We have investigated the phase transition behaviors in function of various process factor including contact size, cell size, and annealing time. As a result, we have observed that programming voltage and writing current of $Ge_1Se_1Te_2$ are more improved than $Ge_2Sb_2Te_5$ material.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.05a
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• pp.66-72
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• 1995

Microstructural features of laser irradiated bulk target which consists of GeSbTe interrmertallic compounds were examined by analytical microscopy. It was found that in addition to vaporization, a liquid expulsion due to laer-material interatction is main contribution of materials removal in the sintered GaSbTe targets, The morphological change is qualitatively discussed in the present article.

• Proceedings of the Korean Ceranic Society Conference
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• 2003.10a
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• pp.192.2-192
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• 2003