• 마이크로전자및패키징학회지
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• 제18권4호
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• pp.33-38
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• 2011

p형 $(Bi_{0.2}Sb_{0.8})_2Te_3$ 분말을 기계적 합금화 공정으로 제조하여 가압소결 후 가압소결온도에 따른 열전특성을 분석하였다. 가압소결온도를 $350^{\circ}C$에서 $550^{\circ}C$로 증가시킴에 따라 상온에서 측정한 Seebeck 계수가 237 ${\mu}V/K$에서 210 ${\mu}V/K$로 감소하고 전기비저항이 2.25 $m{\Omega}-cm$에서 1.34 $m{\Omega}-cm$로 감소하였으며, power factor가 $25.0{\times}10^{-4}W/m-K^2$에서 $32.9{\times}10^{-4}W/m-K^2$로 증가하였다. $350{\sim}550^{\circ}C$의 온도범위에서 가압소결한 시편들 중에서, $500^{\circ}C$에서 가압소결한 $(Bi_{0.2}Sb_{0.8})_2Te_3$ 가압소결체가 상온에서 1.09 및 $75^{\circ}C$에서 1.2의 가장 높은 무차원 성능지수를 나타내었다.

• 한국재료학회지
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• 제10권4호
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• pp.257-263
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• 2000

0.05wt% $SbI_3$를 첨가한 n형 $ Bi_2(Te(_{0.95}Se_{0.05})_3$ 합금분말을 용해/분쇄법으로 제조하여 가압소결 후, 36시간까지의 열처리 시간에 따른 열전특성의 변화 거동을 분석하였다. 열처리 시간이 증가함에 따라 0.05wt% $SbI_3$를 첨가한 n형 $ Bi_2(Te(_{0.95}Se_{0.05})_3$ 가압소결체의 전자 농도가 감소하였다. 0.05wt% $SbI_3$를 첨가한 $Bi_2(Te(_{0.95}Se_{0.05})_3$ 가압소결체는 $2.1{\times}10^{-3}/K$의 성능지수를 나타내었으며 $500^{\circ}C$에서 3시간 열처리 시 $2.35{\times}10^{-3}/K$로 성능지수가 향상되었으나, 12시간 이상 열처리 시에는 전기비저항의 증가에 기인하여 성능지수의 현저한 감소가 발생하였다.

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2000년도 추계총회,초청강연,특별강연,연구발표회
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• pp.58.2-58
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• 2000

• 한국재료학회:학술대회논문집
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• 한국재료학회 2001년도 추계 학술발표강연 및 논문개요집
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• pp.120-120
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• 2001

• 한국주조공학회지
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• 제17권1호
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• pp.76-84
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• 1997

An investigation of the effects of transverse magnetic field on melt convection and macrosegregation in vertical Bridgman growth of Te doped InSb was carried out by means of microstructure observation, the measurement of Te distribution by Hall measurement, electrical resistivity measurement and X-ray analysis. Prior to the experiments, interface stability, convective instability and suppression of convection by magnetic field were examined. A thermosolutal convection in the Te doped InSb melt occurred in the examined growth condition without magnetic field. The effective distribution coefficient, $K_{eff}$, was about 0.35 without magnetic field, 0.45 with magnetic field of 2kG, and 0.7 at 4kG. It was found that the stronger the applied magnetic field was, the more the convection was suppressed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1329-1330
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• 2007

Phase-change random access memory(PRAM) has many advantages compare with the existing memory. For example, fast programming speed, low programming voltage, high sensing margin, low power consume and long cyclability of read/write. Though it has many advantages, there are some points which must be improved. So, we invented and studied new constitution of $Ge_{1}Se_{1}Te_{2}$ chalcogenide material. Actually, the performance properties have been improved surprisingly. However, crystallization time was as long as ever for amorphization time. In this paper, we studied in order to make set operation time and reset operation voltage reduced. In the present work, by alloying Sb in $Ge_{1}Se_{1}Te_{2}$. we could confirm that improved its set operation time and reset operation voltage. As a result, the method of Sb-alloyed $Ge_{1}Se_{1}Te_{2}$ can be solution to decrease the set operation time and reset operation voltage.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.212-212
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• 2009

Thermoelectric devices were used to wide range of application. At present, increasing the efficiency of these devices, in particular, through the preparation of materials showing a high thermoelectric figure of merit, Z, $Bi_2Te_3$ and $Sb_2Te_3$ thin films on Si substrates are deposited by flash evaporation method for thermopile sensor applications. In order to enhance the thermoelectric properties of the thin film, annealing in high vacuum is carried out in the temperature range from 200 to $350^{\circ}C$. The microstructure of the film is investigated by XRD and SEM. The resistivity and Seebeck coefficient of the films are measured by Van der Pauw method and hot probe method respectively. At elevating annealing temperature, the crystallinity and thermoelectrical properties of films are improved by increasing the size of grains. At excessive high annealing temperatures, it is shown that Seebeck coefficient of films is decreased because of Te evaporation. By optimizing the annealing conditions, it is possible to obtain a high performance thin film with a thermoelectric properties.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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• pp.1426-1427
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• 2006

Chalcogenide based phase-change memory has a high capability and potential for the next generation nonvolatile memory device. Fast writing speed, low writing voltage, high sensing margin, low power consume and long cycle of read/write repeatability are also good advantages of nonvolatile phase-change memory. We have been investigated the new material for the phase-change memory. Its composition is consists of chalcogenide $Ge_{1}Se_{1}Te_2$ material. We made this new material to solve problems of conventional phase-change memory which has disadvantage of high power consume and high writing voltage. In the present work, we are manufactured $Ge_{1}Se_{1}Te_{2}/Ge_{2}Sb_{2}Te_{5}/Ge_{1}Se_{1}Te_{2}$ and $Ge_{2}Sb_{2}Te_{5}/Ge_{1}Se_{1}Te_{2}/Ge_{2}Sb_{2}Te_{5}$ sandwich triple layer structure devices are manufactured to investigate its electrical properties. Through the present work, we are willing to ensure a potential of substitutional method to overcome a crystallization problem on PRAM device.

• 한국재료학회지
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• 제20권6호
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• pp.326-330
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• 2010

$CoSb_3$ Skutterudites materials have high potential for thermoelectric application at mid-temperature range because of their superior thermoelectric properties via control of charge carrier density and substitution of foreign atoms. Improvement of thermoelectric properties is expected for the ternary solid solution developed by substitution of foreign atoms having different valances into the $CoSb_3$ matrix. In this study, ternary solid solutions with a stoichiometry of $Co_{1-x}Ni_xSb_3$ x = 0.01, 0.05, 0.1, 0.2, $CoSb_{3-y}Te_y$, y = 0.1, 0.2, 0.3 were prepared by the Spark Plasma Sintering (SPS) system. Before the SPS synthesis, the ingots were synthesized by vacuum induction melting and followed by annealing. For phase analysis X-ray powder diffraction patterns were checked. All the samples were confirmed as single phase; however, with samples that were more doped than the solubility limit some secondary phases were detected. All the samples doped with Ni and Te atoms showed a negative Seebeck coefficient and their electrical conductivities increased with the doping amount up to the solubility limit. For the samples prepared by SPS the maximum value for dimensionless figure of merit reached 0.26, 0.42 for $Co_{0.9}Ni_{0.1}Sb_3$, $CoSb_{2.8}Te_{0.2}$ at 690 K, respectively. These results show that the SPS method is effective in this system and Ni/Te dopants are also effective for increasing thermoelectric properties of this system.

• 한국전기전자재료학회논문지
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• 제23권3호
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• pp.199-205
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• 2010

The crystallization speed (v) of amorphous (InTe)$_x$(GeTe) (x = 0.1, 0.3 and 0.5) films and their thermal, optical and electrical behaviors have been investigated using nano-pulse scanner (wavelength = 658 nm, laser beam diameter < 2 ${\mu}m$), X-ray diffraction (XRD), 4-point probe and UV-vis-IR spectrophotometer. These results were compared with those of $Ge_2Sb_2Te_5$ (GST) film, comprehensively utilized for phase-change random access memory (PRAM). Both v-value and thermal stability of (InTe)$_{0.1}$(GeTe) and (InTe)$_{0.3}$(GeTe) films could be enhanced in comparison with those of the GST. Contrarily, the v-value in the (InTe)$_{0.5}$(GeTe) film was so drastically deteriorated that we could not quantitatively evaluate it. This deterioration is thought because amorphous (InTe)$_{0.5}$(GeTe) film has relatively high reflectance, resulting in too low absorption to cause the crystallization. Conclusively, it could be thought that a proper compositional (InTe)$_x$(GeTe) films (e.g., x < 0.3) may be good candidates with both high crystallization speed and thermal stability for PRAM application.