• Journal of the Korean Crystal Growth and Crystal Technology
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• v.11 no.5
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• pp.211-217
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• 2001

Czochralski법에 의한 ZnWO₄단결정을 [100], [101], [001] 방향으로 성공적으로 성장시켰다. 각 축 방향에 따른 성장조건이 rotation speed, pulling rate, 성장된 결정의 직경 등의 변수를 가지고 조사되어졌다. 성장된 결정의 냉각시 발생되는 균열을 annealing 효과에 의하여 방지할 수 있었다. 성장된 결정의 방위는 Laue back reflection으로 결정하였다. 각 축 방향으로 성장된 결정의 미세구조적 특징이 논하여졌으며, 경도, 열팽창계수 및 유전상수의 물리적 특성이 평가되어졌다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.5 no.1
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• pp.44-49
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• 1995

Abstract The surface of 6H - SiC bulk crystal grown by sublimation process was investigated by optical microscope observation. Since, in the 6H crystal growing, the crystal had the habitual step growth attitude such that the lateral growth rate along the random a - axis orientation was higher than that along the c - axis of the growth direction, then many steps were developed. There were, also, many micropipes on the surface in the form of as-like large voids. However, they were differenciated with pores and cross- sectional shape of them were close to the circle. In this study, many micropipes, planar defects and the growth steps appeared on the grown crystal surface were investigated.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.365-365
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• 2012

스퍼터된 a축 성장된 산화아연 박막의 전기적 및 구조적 특성의 DC 파워에 대한 영향을 c 축 성장된 산화아연 박막과의 비교를 통해 분석하였다. 1~103 ${\Omega}{\cdot}cm$의 낮은 비저항을 갖는 파워를 갖는 조건과 106~108 ${\Omega}{\cdot}cm$의 높은 비저항을 갖는 파워를 갖는 조건에 대한 분석을 진행하였다. 각 조건에 따른 XRD 분석을 통해 낮은 비저항을 갖는 파워를 갖는 조건의 경우 (100) 성장 방향을 강하게 나타내었으나, 높은 비저항을 갖는 파워를 갖는 조건의 경우 약한 (002) 성장 방향을 나타내었다. EDS를 이용한 분석시 낮은 비저항을 갖는 파워의 경우 상대적 으로 oxygen rich 특성을 나타내었다. 이번 연구를 통해 비저항 등 다양한 조건에 따라 결정 성장 방향이 다름을 확인하였으며, 이에 대한 분석을 통해 산화아연 박막의 성장된 조건에 따 라 다양한 전자소자에의 응용 및 분석이 필요함을 확인하였다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.3
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• pp.349-358
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• 1997

meta-Nitroaniline(mNA) crystals were grown from the supercooled melt for the first time. A seed was introduced into the purified mNA melt of 100 ml 0.1 K above the melting temperature ($T_m$ : $112.0^{\circ}C$) and crystal was grown at constant supercooling of 0.1 K. The melt was stirred . mechanically and the crystal was also rotated while the growth proceeds. mNA crystals of size up to $20{\times}15{\times}15 \textrm {mm}^3 and of very high perfection could be grown for the period of one day. The bottom half of the crystal faces are well-faceted and covered by {111} and {021} faces, while the faces of the top half are not well defined. The overall crystal morphology was characterized by the unidirectional growth along one of the polar axes. The absolute direction of preferred growth was determined to be [001] by the pyroelectric measurements. The perfection of the crystal was characterized by synchrotron X-ray topography and optical characterization was made by measuring second harmonic conversion efficiency.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.3
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• pp.406-417
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• 1997

A numerical study was conducted on the optimum magnetic field intensity and asymmetric factor for uniform axial oxygen concentration in 8 inch silicon single crystal growing process by magnetic Czochralski method. For constant shape of cusp field, a change of coil and crucible position were compared. In case of symmetric cusp field, magnetic field intensity variation shows concave downward with crystal growing for uniform, axial oxygen concentration. A numerical results show similar value of standard deviation of average oxygen concentration for uniform oxygen concentration between coil and crucible position change. In case of asymmetric cusp field. asymmetric factor is increased with crystal growing to have uniform oxygen concentration.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.4 no.1
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• pp.57-62
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• 1994

$YbFeCoO_4$ single crystal was grown by floating zone method. The atmospheric condition of the growth was controlled in air and the growth rate was 1~2 mm/hr. After melting the feed rod of the composition of $YbFeCoO_4$, $YbFeCoO_4$ was decomposed to $YbFeCoO_4$ and CoO phase in the initial state of the growth. The liquid composition, however, changed to the direction of the eutectic point along the liquidus line and then stopped at the point in which $YbFeCoO_4$ single crystal could be grown. The growth direction of the crystal was preferred orientation [110], perpendicular to the c-axis in the hexagonal system due to using the polycrystalline seed.

• Analytical Science and Technology
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• v.23 no.2
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• pp.103-108
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• 2010

Single crystals of $ZnWO_4$ with [100], [010] and [001] directions were successfully grown by the Czochralski method. The seed crystals for the single crystal growth of $ZnWO_4$ could be induced by the crystal growth using platinum wires applied by the capillary action from the melt. The growth conditions in each direction were investigated in terms of the variations of rotation speed, pulling rate and diameter of the grown crystals. The formation of cracking in the grown crystals during the cooling process could be prevented by annealing effect. The growth directions of the grown crystals were determined using Laue back reflection. The microscopic characteristics of the grown crystals in each direction were discussed, and their physical properties were evaluated for hardness, thermal expansion coefficients and dielectric constants.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.1
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• pp.84-88
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• 1999

The behavior of oxygen precipitation was investigated in radial direction using Si wafers with different vacancy-related defects generation area. The behavior of oxygen precipitation in radial direction is strongly dependent on the size of vacancy rich area which is related with crystal growth condition. Oxygen precipitation rate is more enhanced in vacancy rich area than that of interstitial rich area. And anomalous oxygen precipitation is generated in the marginal bands of vacancy and interstial area. In V/I boundary, however, oxygen precipitation is suppressed to nearly perfect.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.3 no.2
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• pp.149-156
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• 1993

Polycrystalline silicon was produced from metallurgical-grade Si by unidirectional solidification. Variations of impurity concentration and resistivity in the ingots have been investigated. X-ray diffraction analysis has also been performed to examine the crystal orientation. According to the X-ray diffraction analysis on the polycrystalline silicon, preferential orientation was changed from ( 220) into ( III ) with decreasing growth rate. Also, with increasing growth rate and fraction solidified, the resistivity tends to decrease.

• Korean Journal of Materials Research
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• v.9 no.3
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• pp.295-300
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• 1999

액상의 Ga으로부터 공급되느 기체상태의 Ga과 $NH _3$를 $1050~1150^{\circ}C$의 온도범위에서 직접 반응시켜 사파이어 기판위에 직경이 5~27$\mu\textrm{m}$이고, 높이가 $2~27\mu\textrm{m}$인 육각기둥 형태의 GaN 결정을 성장하였다. GaN 결정의 성장 초기에는 c-축 방향으로 우선 성장된 후 성장시간과 성장온도 및 $NH_3$의 유량이 증가함에 따라 기체상태의 Ga공급이 제한됨으로써 성장률이 둔화됨과 동시에 $\alpha$-축 방향으로 우선 성장되었다. GaN 결정의 크기가 증가함에 따라 결정의 품질이 개선되어 X-선 회절강도와 중성도너에 구속된 엑시톤 관력 발광밴드 (I\ulcorner)의 강도가 증가하고, I\ulcorner 발광밴드의 반치폭이 감소하였다.