scholarly journals Improvement of SiC Crystal Growth Rate and Uniformity via Top-Seeded Solution Growth under External Static Magnetic Field: A Numerical Investigation

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 651
Author(s):  
Minh-Tan Ha ◽  
Le Van Lich ◽  
Yun-Ji Shin ◽  
Si-Young Bae ◽  
Myung-Hyun Lee ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Growth Rate ◽  
Fluid Flow ◽  
Crystal Growth ◽  
Static Magnetic Field ◽  
Crystal Surface ◽  
Solution Growth ◽  
Helmholtz Coils ◽  
External Static Magnetic Field ◽  
Top Seeded Solution Growth

Silicon carbide (SiC) is an ideal material for high-power and high-performance electronic applications. Top-seeded solution growth (TSSG) is considered as a potential method for bulk growth of high-quality SiC single crystals from the liquid phase source material. The crystal growth performance, such as growth rate and uniformity, is driven by the fluid flow and constitutional flux in the solution. In this study, we numerically investigate the contribution of the external static magnetic field generated by Helmholtz coils to the fluid flow in the silicon melt. Depending on the setup of the Helmholtz coils, four static magnetic field distributions are available, namely, uniform vertical upward/downward and vertical/horizontal cusp. Based on the calculated carbon flux coming to the crystal surface, the vertical downward magnetic field proved its ability to enhance the growth rate as well as the uniformity of the grown crystal.

Growth of Large Diameter 4H-SiC by TSSG Technique

2013 ◽  
Vol 740-742 ◽  
pp. 65-68 ◽  
Author(s):  
Kazuhiko Kusunoki ◽  
N. Yashiro ◽  
Nobuhiro Okada ◽  
Kouji Moriguchi ◽  
Kazuhito Kamei ◽  
...  
Keyword(s):  
Growth Rate ◽  
Fluid Flow ◽  
Single Crystal ◽  
Large Diameter ◽  
High Growth ◽  
High Growth Rate ◽  
Solution Growth ◽  
Morphological Stability ◽  
Control Member ◽  
Top Seeded Solution Growth

4H-SiC single crystal with 3-inch diameter was grown by top seeded solution growth (TSSG) technique. We used a new convection control member called “Immersion Guide (IG)” which causes the high and homogenous fluid flow in the solution. As a result, we achieved relatively high growth rate and morphological stability

Modification of Crucible Shape in Top Seeded Solution Growth of SiC Crystal

2018 ◽  
Vol 924 ◽  
pp. 47-50
Author(s):  
Young Gon Kim ◽  
Su Hun Choi ◽  
Yun Ji Shin ◽  
Seong Min Jeong ◽  
Myung Hyun Lee ◽  
...  
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
Temperature Gradient ◽  
Solution Growth ◽  
Cross Sectional ◽  
Dissolved Carbon ◽  
Simulation Results ◽  
Stable Growth ◽  
Top Seeded Solution Growth ◽  
Numerical Approaches

The modified crucible in the top seeded solution growth (TSSG) method was proposed to get the stable growth condition and the enhanced growth rate. The temperature gradient and the distribution of dissolved carbon in the solvent were obtained by numerical approaches. Compared simulation results and experiment, we investigated the region where is the most of dissolved carbon and it is supplied to the seed through what path. The cross-sectional samples of crucibles and grown SiC crystals were systematically analyzed to investigate the effect of the crucible modification on SiC crystal growth.

scholarly journals Flow modification enhancing the growth rate in top seeded solution growth of SiC crystals

RSC Advances ◽  
2019 ◽  
Vol 9 (45) ◽  
pp. 26327-26337 ◽  
Author(s):  
Minh-Tan Ha ◽  
Yeong-Jae Yu ◽  
Yun-Ji Shin ◽  
Si-Young Bae ◽  
Myung-Hyun Lee ◽  
...  
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
Solution Growth ◽  
Multiphysics Simulation ◽  
Flow Modification ◽  
Top Seeded Solution Growth ◽  
Flow Modifier

Based on the verified multiphysics simulation, a model describing C transport contributing to crystal growth was suggested. Based on the further understanding of C transport, the growth rate was enhanced by adopting a flow modifier in the melt.

Filamentation instability in a collisional magnetoplasma with thermal conduction

2009 ◽  
Vol 75 (4) ◽  
pp. 563-573 ◽  
Author(s):  
MAHENDRA SINGH SODHA ◽  
MOHAMMAD FAISAL
Keyword(s):  
Magnetic Field ◽  
Growth Rate ◽  
Static Magnetic Field ◽  
Power Loss ◽  
Thermal Conduction ◽  
Ohmic Heating ◽  
Wave Number ◽  
Main Beam ◽  
Rate Of Growth ◽  
Filamentation Instability

AbstractThis paper presents an analysis of the spatial growth of a transverse instability, corresponding to the propagation of an electromagnetic beam, with uniform irradiance along the wavefront in a collisional plasma, along the direction of a static magnetic field; expressions have been derived for the rate of growth, the maximum value of the rate of growth and the corresponding value of the wave number of the instability. The instability arises on account of the ejection of electrons from regions where the irradiance of the perturbation is large. The energy balance of the electrons taking into account ohmic heating and the power loss of electrons on account of (i) collisions with ions and neutral species and (ii) thermal conduction has been taken into account for the evaluation of the perturbation in electron temperature, which determines the subsequent growth of the instability. Further, the relationship between the electron density and temperature, as obtained from the kinetic theory, has been used. The filamentation instability becomes enhanced with the increase of the static magnetic field for the extraordinary mode while the reverse is true for the ordinary mode. Dependence of growth rate on irradiance of the main beam, magnetic field and a parameter proportional to the ratio of power loss of electrons by conduction to that by collisions has been numerically studied and illustrated by figures. The dependence of the maximum growth rate and the corresponding optimum value of the wave number of the instability on the irradiance of the main beam has also been studied. The paper concludes with a discussion of the numerical results, so obtained.

Effect of Phosphate and Silica on the Rate of Crystallization of Sucrose

2005 ◽  
Vol 1 (5) ◽  
Author(s):  
Ms. Aamarpali Ratna Puri ◽  
S. Kaur
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
Mother Liquor ◽  
Crystal Surface ◽  
Mass Transfer Process ◽  
Sugar Solution ◽  
Local Conditions ◽  
Concentration Difference ◽  
Different Temperatures ◽  
Sucrose Crystals

Sucrose Crystallization is a mass transfer process. Sucrose molecule's migration from solution to crystal is driven by concentration difference between the mother liquor and the crystal surface; the coefficient of super saturation is the most important parameter for the process. Supersaturation of sugar solution depends on the purity and brix of the mother liquor. It has large influence on product's quantity and quality (crystal yield, crystal size and size distribution) and on the cost of production i.e output/hour and energy consumption. However there is still no generally applicable theory, which permits an accurate prediction of the effects of all the factors that govern the industrial processes of crystallization from solution. The crystal growth depends on the viscosity, which further depends on the nature and amount of impurities. If the local conditions are favourable, localized layers of molecules of impurity can statistically remain on the surface for a period of time. On the other hand, if the interaction between the impurity and the layer is weak, then there will be competition between impurity and sucrose molecules thus affecting the sucrose crystal growth rate. In the present study, the growth rate of sugar crystals was studied, using two-litre automatic laboratory vacuum pan, under controlled conditions in the presence of impurities. The effect of phosphate and silica (adding one at time) on the growth rate of sugar crystals was studied at two different temperatures 328 and 338K and with two different seed sizes of sucrose (850 and 600µm). The growth rate was studied at two degrees of supersaturation (1.10 and 1.15). The growth rate of sucrose crystals (with or without added impurities) showed significant increase with the 10°C rise in temperature. The growth rate of sucrose crystals increased with the increase in the level of phosphate but decreased with the increase in the level of silica in sugar solution.

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