• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.12
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• pp.863-866
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• 2013

SiC crystal ingots were grown on 6H-SiC dual-seed crystals with different surface roughness and different seed orientation by a PVT (Physical Vapor Transport) method. 4H and 15R-SiC were grown on seed crystal with high root-mean-square (rms) value. The polytype of grown crystal on the seed crystal with lower rms value was confirmed to be 6H-SiC. On the other hand, all SiC crystals grown on seed crystals with different seed orientation were proven to be 6H-SiC. The surface roughness of seed crystals had no effect on the crystal structure of the grown crystals. However, the crystal quality of 6H-SiC single crystals grown on the on-axis seed were revealed to be slightly better than that of 6H-SiC crystal grown on the off-axis seed.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1999.06a
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• pp.351-360
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• 1999

A large NaX type zeolite crystal of a uniform particle size of 20${\mu}{\textrm}{m}$ are grown with various H2O content by hydrothermal reaction and added seed crystal (2~3 ${\mu}{\textrm}{m}$) to reactant solution as a function of different adding seed levels from 3 to 15 %. The result that increased purity of NaX zeolite above 95% and homogeneity of crystal size by increasing adding seed levels, also decreased crystallization time. It was explained that adding seed to synthesis solution leaded out increase of surface area of physical contact reaction and directed growth of seed crystal, so more rapid consumption of reaction gel as increase seeding levels.

• Progress in Superconductivity and Cryogenics
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• v.1 no.1
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• pp.1-6
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• 1999

The microstructures of top seed mult processde $\textrm{YBa}_2\textrm{Cu}_3\textrm{O}_7$.$\delta$ single crystal were studied. Although shape of the seed was not faceted. the growth shape of Y123 single crystal was faceted. It was observed that Y211 phases were trapped in specific spaces of the faceted region. From the microstructural investigation. it was suggested that the segregation of Y211 is due to the difference of growth rates in crystal direction. When a single crystal was grown by the single seed with stepped multi surfaces. a microstrue was grown from multi-seed. The microstructure show the possibility of multi-seed growth. Corn kernel like structure without Y211 phase was observed and seemed to be formed by the diffusion reaction between Y211 phase in crystal and liquid wetted on the crystal. the diagonal line on Y123 crystal was observed that it was formed by the corn kernel like structure.

• Korean Journal of Crystallography
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• v.5 no.2
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• pp.93-99
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• 1994

Growth form and surface morphology of NYAB single crystal grown by TSSG technique using a K2O/3MoOS/0.5B203 flux was investigated. In the crystal grown from <100> or <120> seed, prismatic and (101) faces were well developed with different size each other. (001) face was also developed in the crystal grown from <001> seed. While growth hillocks were observed on the prismatic face of the crystal grown from <100> seed, surface striations parallel to neighbor (101) faces were formed on that face of the crystal grown from <001> seed. The (101) faces were grown by two dimensional nucleation growth. (001) face which was developed at slow growth velocity of [001] direction was grown by screw dislocation Anisotropy of growth velocity as to seed orientation affected on crystal morphology and surface morphology.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.4
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• pp.371-376
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• 1999

A large NaX type zeolite crystal of a uniform particle size of 20$\mu\textrm{m}$ are grown with various {{{{{H}_{2}O}}}} content by hydrothermal reaction and added seed crystal (2~3$\mu\textrm{m}$) to reactant solution as a function of different adding seed levels from 3 to 15%. The result that increased purity of NaX zeolite above 95% and homogeneity of crystal size by increasing adding seed levels, also decreased crystallization time. It was explained that adding seed to synthesis solution leaded out increase of surface area for physical contact reaction and directed growth of seed crystal, so more rapid consumption of reaction gel as increase seeding levels.

• Progress in Superconductivity and Cryogenics
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• v.24 no.3
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• pp.35-40
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• 2022

To fabricate large grain YBCO bulk superconductors by melt process, Sm123 single crystal with a high melting point are mostly used as seeds. However, it also uses Y123 film deposited on MgO single crystal substrate. This study investigated the growth behavior of the Y123 grain during a melt process when single grain YBCO bulk was used as a seed. Single grain Y123 bulk was grown when the seed size was small. When the seed size was relatively large, multiple grains were grown but the grains were still large. Y123 seed crystal was completely decomposed during high temperature anneal at 1040℃ and new Y123 crystals were nucleated during a slow cooling stage below a peritectic temperature. Thereafter, newly formed Y123 crystals from the seed area are thought to grow into the Y1.8 powder compact. The crystallographic orientations of newly nucleated Y123 grains are independent of the crystallographic orientation of Y123 seed. It is thought that the crystallographic orientation of newly nucleated Y123 crystal can be controlled by using Y211-free Y123 single crystal as a seed of homo-seeding melt growth.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.1
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• pp.6-13
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• 1999

NaX zeolite crystal were grown from seed elements of synthetic NaX(2~3$\mu\textrm{m}$) Powder in a mother liquor having an approximate reactant composition ${4.12{Na}_{2}O{\cdot}{Al}_{2}{O}_{3}{\cdot}3.5{SiO}_{2}{\cdot}593{H}_{2}O$.The result was that crystallization time of NaX zeolite was reduced with adding seed materials to the initial mixture and crystal size was reduced . but with increasing crystallization time, NaX zeolite. In this study, We investigated detailed factors which NaX crystal has been determined by a combination of SEM, XRD, FT-IR, and BET.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.12 no.4
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• pp.190-195
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• 2002

NaX zeolite crystals of a uniform particle size of 50 $\mu$m were grown by continuous crystallization method from seed crystals (10~20 $\mu$m) added into a 0.5~2.0 g mother liquor having a composition $3.5Na_2O : Al_2O_3: 2.1SiO_2: 1000H_2O$. In order to investigate the crystal growing by continuous method, the mother solution was supplied after 7 days, 5 days, 3 days and 1 day, respectively. The seeding resulted in an increase in the fraction of large crystals compared with unseeded batches and successfully led to an uniform NaX zeolite crystal. It was postulated that the seeding in the synthesis mixture leaded out increase of surface area for physical contact reaction and directed growth of seed crystal without the nucleation in the synthesis gel.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.232-232
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• 2006

SiC single crystal Ingots were prepared onto different seed material using sublimation PVT techniques and then their crystal quality was systematically compared. In this study, the conventional SiC seed material and the new SiC seed material with an inserted SiC epitaxial layer on a seed surface were used as a seed for SiC bulk growth. The inserted epitaxial layer was grown by a sublimation epitaxy method called the CST with a low growth rate of $2{\mu}m/h$ N-type 2"-SIC single crystals exhibiting the polytype of 6H-SiC were successfully fabricated and carrier concentration levels of below $10^{17}/cm^3$ were determined from the absorption spectrum and Hall measurements. The slightly higher growth rate and carrier concentration were obtained in SiC single crystal Ingot grown on new SiC Seed materials with the inserted epitaxial layer on the seed surface, maintaining the high quality.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.3
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• pp.222-226
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• 2008

With different seed adhesion methods, we obtained two different aspects with or without micro-bubble in the interface between a seed and a dense graphite seed holder. To improve the quality of SiC wafer, we introduced a sucrose caramelizing step at the seed adhesion using the sucrose, The n-type 2 inch single crystal exhibiting the polytype of 6H-SiC were successfully fabricated and carrier concentration levels of about $10^{16}/cm^3$ was determined from Hall measurements, As compared to the characteristics of SiC crystal grown with micro-bubble in the interface between the seed and the dense graphite seed holder, the SiC crystal grown without micro-bubble definitely exhibited lower resistivity, lower micropipe density and higher mobility relatively.