• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기물성,응용부문
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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.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 디스플레이 광소자분야
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• pp.119-122
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• 2004

This paper discovers that we form holographic grating in AsGeSeS thin film. Holographic grating is not developed in the length of 10,20,40nm, while it is formed in the thin film of 80nm though it shows very low diffraction efficiency. On the contrary, holographic grating is established in every thin film of Ag(10nm)/AsGeSeS(10,20,40,80nm). Lattice in 10,20 nm thin film builds up, and immediately disappears. In the case of 40nm thin film, even if holographic grating is made up, it seems to have a low diffraction efficiency. Apart from 10,20,40nm, it shows the highest diffraction efficiency in the thin film of 80nm.

• 분석과학
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• 제15권5호
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• pp.439-444
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• 2002

이 연구는 E-O-V ICP-AES를 이용하여 As, Se, Ge에 대한 분석적 특성을 PN과 USN, 그리고 HG를 이용하여 비교 조사하였다. 특히 세 가지 원소들의 수소화물 형성을 위한 최적의 조건을 찾기 위하여 $NaBH_4$와 HCl의 농도 변화에 대한 신호세기의 영향을 면밀히 조사하여 보았다. 수소화물 발생화 장치를 이용하였을 때가 PN과 USN 이용시 보다 세 가지 원소 모두 훨씬 좋은 감도를 얻을 수 있었고, 그 검출한계는 PN 보다는 약 100배, USN 보다는 약 10배 향상시킬 수 있었다.

• E2M - 전기 전자와 첨단 소재
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• 제10권2호
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• pp.105-112
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• 1997

Undoped and Co$^{2+}$-doped Zn$_{4}$GeSe$_{6}$ single crystals were grown by the Chemical Transport Reaction method using iodine as a transporting agent. The crystal structure of these compounds determined by X-ray diffraction analysis was monoclinic structure. The direct energy gaps of these compounds were measured and the temperature dependence of the optical energy gap were closely investigated over the temperature range 10-290K. The temperature dependence of the optical energy gap is well presented by the Varshni equation. Also the optical absorption peaks of Zn$_{4}$GeSe$_{6}$ :Co$^{2+}$ single crystal observed, centered at 5437, 6079, 7142, 12950, 13462, 14786 and 15735 $cm^{-1}$ /, can be explained in terms of the electronic transitions of Co$^{2+}$ ions located at Td symmetry of the host materials. According to the crystal-field theory, the crystal-field, Racah and spin-orbit coupling parameters obtained from the absorption bands are given by Dq = 361$cm^{-1}$ /, B = 655$cm^{-1}$ / and .lambda. = 284$cm^{-1}$ / respectively.ively.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1992년도 춘계학술대회 논문집
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• pp.30-33
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• 1992

This thesis was investigated on ion-induced characteristics in a-$Se_{75}Ge_{25}$ positive and negative resists for focused-ion-beam microlithogaphy. The exposed a-$Se_{75}Ge_{25}$ inorganic thin film shows an increase in optical absorption after exposure to~$10_{16}$ dose of Ga+. The observed shift in the absorption edge toward longer wavelengths is consistent with that in films exposed to band-gap photons(~$10^{21}$photons/cm2). This result may be related with microstructural rearrangements with in the short range of SeGe network. Due to changes in the short range order, the chemical bonding may be affected, which results in increased chemical dissolution in ion-induced film. Also, this resist exhibits good thermal stability because of its high Tg(~$220^{\circ}C$). When focused ion beams are used for direct exposure of resist over a substrate, unwanted implantation of the substrate may be an issue. A possible way to avoid this is to match the thickness of the resist to the range of ions in the resist. Thin aspect is currently under investigation.

• 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 2005년도 춘계학술대회 논문집 디스플레이 광소자 분야
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• pp.88-91
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• 2005

본 논문에서는 비정질 As-Ge-Se-S 박막의 에칭 레이트를 측정하였으며 As-Ge-Se-S 박막에 회절격자를 형성 시킨 후 선택적 에칭을 통한 엠보싱 홀로그램을 제작하였다. NaOH 수용액으로 0.26N, 0.33N, 0.40N 농도로 변화시키며 수행하였으며 에칭 시간에 따른 에칭되는 두께의 변화를 측정하였다. 에칭 레이트는 NaOH 용액의 농도가 0.26N, 0.33N, 0.40N 일 때 각각 $2.5{\AA}/s$, $3.3{\AA}/s$, $3.9{\AA}/s$ 였다. 또한 2차원 엠보싱 회절격자를 형성 시킨후 0.26N NaOH용액으로 60초간 선택적 에칭을 수행하여 AFM(Atomic Force Microscopy) 으로 측정한 결과 선명한 엠보싱 형태의 회절격자를 확인 할 수 있었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 춘계학술대회 논문집 디스플레이 광소자 분야
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• pp.92-95
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• 2005

The silver photodoping effect in amorphous AsGeSeS chalcogenide thin films for holographic recording has been investigated using a HeNe laser ($\lambda$=632.8 nm). The chalcogenide films prepared in this work were thinner in comparison with the penetration depth of recording light ($d_p$=1.66 mm). The variation of the diffraction efficiency $(\eta)$ in amorphous chalcogende films exhibits a tendency, independently of the Ag photodoping. That is, n increases relatively rapidly at the beginning of the recording process, reaches the maximum $({\eta}_{max})$ and slowly decreases. In addition, the value of ${\eta}_{max}$ depends strongly on chalcogenide film thickness(d) and its peak among the films with d = 40, 80, 150, 300, and 633 nm is observed at d = 150 nm (approximately 1/2n), where n is refractive index of the chalcogenide (n=2.0). The ${\eta}$ is largely enhanced by Ag photodoping into the chalcogenides. In particular, the value of hmax in a bilayer of 10-nm-thick Ag/150-nm-thick AsGeSeS film is about 1.6%, which corresponds to ~20 times in comparison with that of the AsGeSeS film (without Ag).

• E2M - 전기 전자와 첨단 소재
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• 제1권4호
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• pp.295-302
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• 1988

본 연구에서는 미세패턴 형성을 위한 비정질 $Se_{75}Ge_{25}$박막의 네가티브형 포토레지스토에 대하여 고찰하였다. 습식현상공정을 통해 대비도가 포지티브형인 경우 1.4였고 네가티브형인 경우 2.9를 나타내어 네가티브형인 경우가 미세선폭 조절능력이 더 우수함을 알 수 있었다. 표면사진으로부터 약 1.mu.m정도의 미세패턴을 얻었음을 확인할 수 있었다.

• 한국진공학회지
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• 제2권1호
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• pp.85-91
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• 1993

본 연구에서는 광기록 매질 중 광유기효과가 큰 비정질 As40Se15S35Ge10박막의 증착각도변화에 따른 구조 및 광학적 구조 및 광학적 물질특성에 대해 고찰하였다. 준비된 bulk와 박막이 비정질상(Amorphous phase)임을 XRD 분석을 통해 확인하였다. 특히, 증착각도의 변화에 따른 비정질 As40Se15S35Ge10박막에서의 유리질 천이온도의 변화와 상분리 현상을 연구하였다. 유리질 천이온도의 확인은 DSC, DTA, TGA를 이용한 분석실험을 통해 수행하였다. 실험 결과 벌크의 유리질 천이 온도는 약 $238^{\circ}C$였고, 0。, 60。, 80。로 증착된 박막은 각각 $202^{\circ}C$, $229^{\circ}C$, $201^{\circ}C$였으며 80。로 증착된 박막의 경우 가장 낮은 값을 보였다. 또한 연속상과 분산상으로의 상 분리 현상은 편광현미경에 의한 광학구조분석과 SEM-EDS를 이용한 표면확인 및 성분분석으로 관찰하였다.