• Journal of the Korean Crystal Growth and Crystal Technology
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• v.26 no.4
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• pp.135-138
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• 2016

It was observed that the single grain of crystallite growth behavior in AlN (Aluminum Nitride) single crystal growth by PVT (Physical Vapor Transport) method. The single grain of AlN was grown in sequent experiments and adjacent crystallites were joined together after small grain was grown. The sequential results of those grains observed by stereoscopic microscope were reported.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.22 no.6
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• pp.265-268
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• 2012

The growth of AlN single crystals of large size and good quality is of prime importance for UV LEDs and power devices applications. However, the crystals having the size of more than 1 inch and high quality have not been reported in the world. In the PVT growth of AlN, the crystal morphology of as grown were important because the preferred orientation of growth of it was evaluated for growth rate increase. In the present study, the AlN single crystals grown by PVT process were evaluated by the side of the growth morphology. Optical microscopic characterization was carried out to observe the shape of the crystals and the growth facets. Furthermore the growth habit of it were discussed by observation of the surface of AlN crystals.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.24 no.2
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• pp.54-58
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• 2014

AlN (Aluminum Nitride) crystals were grown by a PVT (Physical Vapor Transport) method and were characterized to phases on the growth temperature. The crystals phase and morphology were analyzed using an optical stereo-microscope and the optimum temperature for the growing was determined. In this report, the characteristics of the AlN crystals grown at various temperatures were reported.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.30 no.5
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• pp.163-167
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• 2020

Ring-shaped SiC (Silicon carbide) polycrystals used as an inner material in semiconductor etching equipment was manufactured using the PVT (Physical Vapor Transport) method. A graphite cylinder structure was placed inside the graphite crucible to grow a ring-shaped SiC polycrystal by the PVT method. The crystal polytype of grown crystal were analyzed using a Raman and an UVF (Ultra Violet Fluorescence) analysis. And the microstructure and components of SiC crystal were identified by a SEM (Scanning Electron Microscope) and EDS (Energy Disruptive Spectroscopy) analyses. The grain size and growth rate of SiC polycrystals fabricated by this method was varied with temperature variation in the initial stage of growth process.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.34 no.2
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• pp.41-47
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• 2024

In this study, the resistance characteristics of semi-insulating SiC single crystals grown using the PVT method were investigated, considering the purity level of SiC source powders used in PVT growth and the cooling procedure after crystal growth. Two β-SiC powders with different purities were employed, and the cooling rate after growth was adjusted to achieve various resistance values. 4-inch HPSI-SiC ingots were grown using the PVT method, utilizing SiC powders with low nitrogen concentration and relatively high nitrogen concentration. These ingots were then subjected to different cooling procedures to modify the cooling rate. Transmission/absorption spectra and crystal quality of the grown crystals were analyzed through UV/VIs/NIR spectroscopy and X-ray rocking curve analysis, respectively. Additionally, electrical properties were investigated through non-contact resistivity analysis to identify the dominant factors influencing resistivity properties.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.27 no.2
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• pp.65-69
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• 2017

AlN single crystal was thermally treated at 1600, 1700 and $1800^{\circ}C$ in the ambient pressure of under 100 torr. AlN single crystal was obtained by PVT (Physial Vapor Transport) method using by a facility having a growth part which was heated by RF (Radio Frequency) induction heating. The single crystal specimens surface was evaluated by optical microscope and it was recognized that their morphology was varied with the heat treatment temperature and a set ambient pressure. In this report, the optical microscopic results were reported. According to the increase of temperature the crystal surface was etched thermally. It was evaluated by appearance of small pits on the crystal surface.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.28 no.4
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• pp.148-151
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• 2018

A large single crystal of AlN was grown by PVT (Physical Vapor Transport) method. The AlN crystal shaped hexagonal of the diameter of about 46 mm and the thickness of 7.6 mm was grown using 33 mm seed crystal which was grown and made by ourselves. We tried to find out repeatable growth possibility for AlN crystal growth and then to evaluate the repeatability of the growth condition of the temperature of $1950{\sim}2100^{\circ}C$ and the ambient pressure of 0.1~1 atm.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.25 no.1
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• pp.32-34
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• 2015

AlN Single Crystal were grown by PVT (Physical vapor transport) method on bulk seed. It was performed by high-frequency induction-heating coil. AlN source powder was loaded at bottom side of the carbon crucible and the crystal seed was loaded at the upper side of the crucible. The temperature conditions of the growth was varied $2000{\sim}2100^{\circ}C$ and the surrounding pressure was $1{\times}10^{-1}{\sim}200$ Torr. And the hot-zone of the heating position was controlled elaborately according to growth. The 17 mm-diameter, 7 mm-thickness AlN single crystal is obtained for about 600 hours growing. It was recognized that the growth direction of as grown crystal was R[011] by the Laue X-Ray camera measurement.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.25 no.1
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• pp.1-5
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• 2015

For the special usage, the effort of developing AlN single crystals has been very hot in the world. The AlN-base UV LEDs are used on the field of sterilization, purification, curing and analyzing, which can advance human's living and medical processes etc.. AlN single crystals were grown by the PVT (Physical vapor transport) method. On the growing process, carbon crucibles with three different types such as normal size, taller than normal and wider than normal were used for comparison. The processing temperature was in the range of $1900{\sim}2100^{\circ}C$ and ambient pressure was 200~1 Torr. When the taller crucible was used, the sublimation mass was greater than normal dimension one but the best condition of growth changes widely. However the wider one gave much sublimation mass and growing condition was more stable than normal dimension. On limited growing furnace system, the changes of crucible dimension of PVT method provide the change of best condition for growth rate, as-grown crystal quality and growth condition stability.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.32 no.1
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• pp.1-6
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• 2022

In this research, a ring-shaped silicon carbide (SiC) single crystal manufactured using the PVT (Physical Vapor Transport) method was proposed to be applied to a SiC focus ring in semiconductor etching equipment. A cylindrical graphite structure was placed inside the graphite crucible to grow a ring-shaped SiC single crystal by the PVT method. SiC single crystal ring without crack was successfully obtained in case of using SiC single crystal wafer as a seed. A plasma etching process was performed to compare plasma resistance between the CVD-SiC focus ring and the PVT-SiC focus ring. The etch rate of ring materials in PVT-single crystal SiC focus ring was definitely lower than that of CVD-SiC focus ring, indicating better plasma resistance of PVT-SiC focus ring.