• Proceedings of the Korean Ceranic Society Conference
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• 2003.04a
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• pp.221.2-221
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• 2003

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.32 no.6
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• pp.219-224
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• 2022

CaF₂ single crystal has a large band gap (12 eV), and it is used for optical windows, prisms, and lenses due to its excellent transmittance in a wide wavelength range and low refractive index. Moreover, it is expected to be one of the materials for ultraviolet transmissive laser optical components. CaF₂ belongs to the fluoride compounds and has a face-centered cubic (FCC) structure with three sub-lattices. The representative method for CaF₂ single crystal growth is Czochralski, which method has the advantages of high production efficiency and the ability to make large crystals. In this study, X-ray diffraction (XRD), X-ray rocking curves (XRC) measurement, and chemical etching were performed to analyze the crystallinity and defect density of the CaF₂ single crystals, grown by the Czochralski method. Fourier-transform infrared spectroscopy (FT-IR) and UV-VIS-NIR spectroscopy systems were used to investigate the optical properties of the CaF₂ crystal. The provability of various applications, including UV application, was systematically investigated with various analysis results.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.1
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• pp.11-18
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• 1996

Grown-in defects like OISF and FPD in the large diameter(> 8 inch)of silicon crystal are characterized. It was revealed that the presence of the ring-patterned OISF would deterorate the minority life time of the silicon crystal. Through the cooling experiment from the $1250^{\circ}C$, the nucleation of the OISF was confirmed to follow the homogeneous nucleation and growth process. In addition to OISF nucleus, crystal originated particle, which was known to be closely related with FPD (Flow Pattern Defects), was found to depend on the pulling rate of the crystal. Combination of the lower rate of the pulling and the faster cooling near the $950^{\circ}C$ is proposed to be effective method in reducing the generation of these grown-in defects.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.10 no.6
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• pp.381-388
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• 2000

The temperature and velocity fluctuations occurred by the baroclinic instability in the melt for Czochralski crystal growth method were experimentally investigated. Wood's metal, which has similar Pr number to the silicon melt, was used as the working fluid and azimuthal velocity was measured using incorporated magnet probe. The azimuthal velocities near the free surface are faster than velocities near the bottom and the rotational velocities near the model crystal become very fast. The results of measured temperature fluctuation as increasing rotation rate were shown that baroclinic instability occurred at the region of Ro<1.01, Ta>$9.63{\times}10^8$. In these region, the fluctuations of temperature and velocity have the same frequency.

• Proceedings of the Korea Crystallographic Association Conference
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• 2005.11a
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• pp.12-13
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• 2005

• Journal of the Semiconductor & Display Technology
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• v.11 no.2
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• pp.39-43
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• 2012

This paper presents a study on the design of a pulling module for silicon ingot and an apparatus of manufacturing silicon single crystal ingot using the same method. The pulling module is conceptually designed by using TRIZ. Czochralski method(CZ) is representative way to manufacture single crystal ingot for wafers. The seed can be broken by high tension which is caused by large weight of a silicon ingot. The solution of this problem has been derived using 6SC(6 steps creativity)TRIZ. The pulling module is actuated by DC motor and rollers. High tension in the seed is removed by the rotate-elevate motion of rollers in the pulling module. A rubber belt is included in the rotate-elevate mechanism for increasing friction between rollers and silicon ingot.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.25 no.2
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• pp.68-73
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• 2015

Single crystals of $Yb^{3+}$ doped $Y_3Al_5O_{12}$ up to 25 at.% were grown by the Czochralski method. Using the pulling rate of 0.8 mm/h and the rotation rate of 10 rpm, single crystals with diameters of up to 40 mm and lengths up to 160 mm were obtained. The growth atmosphere was either pure nitrogen or the mixture of nitrogen and oxygen. The crystal was bluish green when using pure nitrogen and the crystal was colorless when using the mixture of 99 % nitrogen and 1 % oxygen. The concentration of $Yb^{3+}$ ions decreased with increasing the length of the crystal and $Yb^{3+}$ concentration of core area was slightly higher than the other areas in the compositional analysis. The fluorescence lifetime decreased with increasing the doping concentration of $Yb^{3+}$ ions.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.20 no.2
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• pp.65-68
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• 2010

$Sr_{0.6}Ba_{0.4}Nb_2O_6$ (60SBN) and $Sr_{0.75}Ba_{0.35}Nb_2O_6$ (75SBN) single crystals were grown by Czochralski method. Growing direction was <001>, and as-grown crystals has well-developed (001) plane. Temperature- and frequency dependence of dielectric constant represent relaxor ferroelectrics. 60SBN has wider optical transmittance than 75SBN.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1999.06a
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• pp.3-26
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• 1999

We have successfully grown <111>-oriented (La,Sr)(Al,Ta)$O_3$(LSAT) mixed-perovskite single crystals and <0001>-oriented $Ca_8La_2(PO_4)_6O_2$(CLPA) single crystals with the apatite structure by the Czochralski method. The compositional and lattice parameter uniformity of the crystals are discussed in relation to the growth conditions. Since LSAT and CLPA single crystals have excellent lattice matching with GaN, they ar promising as new substrates for the growth of high quality GaN epitaxial layers.

• Journal of the Korean Ceramic Society
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• v.39 no.8
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• pp.711-714
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• 2002

The Ce, Mn: $LiTaO_3$ crystals were grown by Czochralski method in congruent ${\varphi}$3＂ $LiTaO_3$ single crystal growing conditions. Concentrations of Ce and Mn in melt were respectively 0.1 mole%. As-grown crystals were red, transparent and the grown crystals were tested with oxidation/reduction treatment for clor and other properties. Influence of Ce and Mn dopants on $LiTaO_3$ crystal properties was discussed. And the nonlinear optical properties of the Ce, Mn: $LiTaO_3$ crystal are being studied.