Analysis of the carbon transport near the growth interface with respect to the rotational speed of the seed crystal during top-seeded solution growth of SiC

2016 ◽  
Vol 55 (12) ◽  
pp. 125601 ◽  
Author(s):  
Tomonori Umezaki ◽  
Daiki Koike ◽  
Shunta Harada ◽  
Toru Ujihara
Keyword(s):  
Rotational Speed ◽  
Seed Crystal ◽  
Solution Growth ◽  
Growth Interface ◽  
Top Seeded Solution Growth ◽  
Carbon Transport

Improvement of Surface Morphology by Solution Flow Control in Solution Growth of SiC on Off-Axis Seeds

2015 ◽  
Vol 821-823 ◽  
pp. 31-34 ◽  
Author(s):  
Tomonori Umezaki ◽  
Daiki Koike ◽  
S. Harada ◽  
Toru Ujihara
Keyword(s):  
Flow Direction ◽  
Seed Crystal ◽  
Solution Growth ◽  
Rotational Axis ◽  
Solution Flow ◽  
Step Flow ◽  
Unidirectional Flow ◽  
Novel Method ◽  
Set Up ◽  
Top Seeded Solution Growth

The solution growth of SiC on an off-axis seed is effective on the reduction of threading dislocations. We proposed a novel method to grow a SiC crystal on an off-axis seed by top-seeded solution growth (TSSG). In our previous study, a unidirectional solution flow above a seed crystal is effective to suppress surface roughness in the growth on the off-axis seed. However, it is difficult to apply the unidirectional flow in an axisymmetric TSSG set-up. In this study, the unidirectional flow could be achieved by shifting the rotational axis away from the center of the seed crystal. As a result, the smooth surface was obtained in the wider area where the solution flow direction was opposite to the step-flow direction.

Effect of Melt-Back Process on the Quality of Grown Crystal in SiC Solution Growth

2019 ◽  
Vol 963 ◽  
pp. 75-79 ◽  
Author(s):  
Kotaro Kawaguchi ◽  
Kazuaki Seki ◽  
Kazuhiko Kusunoki
Keyword(s):  
Dislocation Density ◽  
Grown Crystal ◽  
Early Stage ◽  
Seed Crystal ◽  
Solution Growth ◽  
Crystal Quality ◽  
Top Seeded Solution Growth ◽  
Koh Etching

We investigated the effect of a melt-back process on the quality of the grown crystal in 4H-SiC solution growth. In our experiments, the crystal was grown by top-seeded solution growth (TSSG) method with and without melt-back, following which the quality of the obtained crystals was compared. When solution growth was carried out without melt-back, solvent inclusions and a different polytype were observed. When molten KOH etching was conducted, the dislocation density in the crystals at the early stage of growth became much higher than that in a seed crystal. Solvent inclusions, a different polytype, and an increase in dislocations were suppressed when solution growth was performed with melt-back. It was confirmed that melt-back is necessary to prevent the deterioration of crystal quality at the early stage of solution growth.

Top-Seeded Solution Growth of 3 Inch Diameter 4H-SiC Bulk Crystal Using Metal Solvents

2014 ◽  
Vol 778-780 ◽  
pp. 79-82 ◽  
Author(s):  
Kazuhiko Kusunoki ◽  
Kazuhito Kamei ◽  
Nobuhiro Okada ◽  
Koji Moriguchi ◽  
Hiroshi Kaido ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Growth Process ◽  
Single Crystal Growth ◽  
Solution Growth ◽  
Process Conditions ◽  
Process Stability ◽  
Growth Interface ◽  
Formation Technique ◽  
Top Seeded Solution Growth

We performed top-seeded solution growth of 4H-SiC for obtaining longer length crystal. Si-Cr and Si-Ti melts were used as solvents. Meniscus formation technique was applied to the present study. Special attention was paid to improve the process stability during long-term growth. One of major technological problems in the solution growth is that the precipitation of polycrystalline SiC which hiders the stable single crystal growth. Another problem is the fluctuation of supersaturation at the growth interface during the growth. Through the optimization of growth process conditions, we have successfully grown 4H-SiC single crystals up to 14 mm long with three-inch-diameter, and evaluated their crystalline quality.

Top-Seeded Solution Growth of 4H-SiC Bulk Crystal Using Si-Cr Based Melt

2012 ◽  
Vol 717-720 ◽  
pp. 61-64 ◽  
Author(s):  
Hironori Daikoku ◽  
M. Kado ◽  
H. Sakamoto ◽  
Hiroshi Suzuki ◽  
T. Bessho ◽  
...  
Keyword(s):  
Growth Rate ◽  
Seed Crystal ◽  
Solution Growth ◽  
Bulk Crystals ◽  
High Quality ◽  
Cross Sectional ◽  
Formation Technique ◽  
Top Seeded Solution Growth ◽  
Microscopy Images

We have grown high-quality long cylindrical (12 mm thick) 4H-SiC bulk crystals by the meniscus formation technique, which was first applied for the solution growth of bulk SiC. It enabled long-term growth by suppressing parasitic reactions such as polycrystal precipitation around the seed crystal. In addition, we could control the growth angle from −22° to 61° by adjusting the meniscus height. The thickness of the grown cylindrical crystals was 12 mm, which is the largest reported until now, and corresponded to a growth rate of 0.6 mm/h. Smooth morphology growth was maintained on the (000-1) C-face. In cross-sectional transmission optical microscopy images, few solvent inclusions and voids were observed. XRD measurements revealed that the FWHM values of the grown crystals were almost the same as those of the seed crystal.

Solution Growth of SiC Crystal with High Growth Rate Using Accelerated Crucible Rotation Technique

2006 ◽  
Vol 527-529 ◽  
pp. 119-122 ◽  
Author(s):  
Kazuhiko Kusunoki ◽  
Kazuhito Kamei ◽  
Nobuhiro Okada ◽  
Nobuyoshi Yashiro ◽  
Akihiro Yauchi ◽  
...  
Keyword(s):  
Growth Rate ◽  
High Growth ◽  
Graphite Crucible ◽  
High Growth Rate ◽  
Solution Growth ◽  
Growth Interface ◽  
Rotation Technique ◽  
Stable Growth ◽  
Crucible Rotation ◽  
Carbon Transport

We performed solution growth of SiC single crystals from Si-Ti-C ternary solution using the accelerated crucible rotation technique (ACRT). It was confirmed that the growth rate exceeding 200 μm/hr was achievable by several ACRT conditions. This high growth rate might be due to the enhancement of the carbon transport from the graphite crucible to the growth interface using the ACRT. Moreover, the incorporation of inclusions of the Si-Ti solvent in the grown crystal was significantly suppressed by using the ACRT. It was thought that the intensive convection near the growth interface resulted in not only the marked increase of SiC growth rate but also the superior homogeneity in the surface morphology. It was concluded that faster stable growth can be accomplished in the SiC solution growth using the ACRT.

Control of Interface Shape by Non-Axisymmetric Solution Convection in Top-Seeded Solution Growth of SiC Crystal

2015 ◽  
Vol 821-823 ◽  
pp. 18-21 ◽  
Author(s):  
Daiki Koike ◽  
Tomonori Umezaki ◽  
Kenta Murayama ◽  
Kenta Aoyagi ◽  
S. Harada ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Flow Direction ◽  
Solution Growth ◽  
Interface Shape ◽  
Solution Flow ◽  
Growth Interface ◽  
Axisymmetric Solution ◽  
3 Dimensional ◽  
Unidirectional Flow ◽  
Top Seeded Solution Growth

We achieved the convex growth interface shape in top-seeded solution growth of SiC applying non-axisymmetric solution convection induced by non-axisymmetric temperature distribution. The detailed solution flow, temperature distribution and carbon concentration distribution were calculated by 3-dimensional numerical analysis. In the present case, the solution flow below the crystal was unidirectional and the supersaturation was increased along the solution flow direction. By the rotation of the crystal in the unidirectional flow and the temperature distribution, we successfully obtained the crystal with the convex growth interface shape.

scholarly journals Improvement of Growth Interface Stability for 4-Inch Silicon Carbide Crystal Growth in TSSG

Crystals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 653 ◽  
Author(s):  
Botao Liu ◽  
Yue Yu ◽  
Xia Tang ◽  
Bing Gao
Keyword(s):  
Silicon Carbide ◽  
Crystal Growth ◽  
Flow Field ◽  
Industrial Production ◽  
Solution Growth ◽  
Interface Instability ◽  
Growth Interface ◽  
Interface Stability ◽  
Large Size ◽  
Top Seeded Solution Growth

The growth interface instability of large-size SiC growth in top-seeded solution growth (TSSG) is a bottleneck for industrial production. The authors have previously simulated the growth of 4-inch SiC crystals and found that the interface instability in TSSG was greatly affected by the flow field. According to our simulation of the flow field, we proposed a new stepped structure that greatly improved the interface stability of large-size crystal growth. This stepped structure provides a good reference for the growth of large-sized SiC crystals by TSSG in the future.

Increase in the Growth Rate by Rotating the Seed Crystal at High Speed during the Solution Growth of SiC

2014 ◽  
Vol 778-780 ◽  
pp. 63-66 ◽  
Author(s):  
Tomonori Umezaki ◽  
Daiki Koike ◽  
Atsushi Horio ◽  
S. Harada ◽  
Toru Ujihara
Keyword(s):  
Numerical Simulation ◽  
Growth Rate ◽  
Carbon Concentration ◽  
Concentration Gradient ◽  
High Speed ◽  
Rotation Speed ◽  
Seed Crystal ◽  
Solution Growth ◽  
Growth Interface ◽  
Wide Range

We studied the effect of rotation speed of seed crystal on the growth rate during the solution growth of SiC. The growth rate increased with increasing rotation speed of the seed crystal. The increase in the growth rate was observed in relatively wide range of carbon concentration. According to the numerical simulation, the carbon concentration gradient near the growth interface under 150 rpm condition is larger than 20 rpm (ACRT) condition. This indicates that increase in the growth rate is caused by the increase in the carbon concentration gradient of the diffusion layer.

YMgB5O10 crystal preparation and attractive multi-wavelength emission characteristics of doping Nd3+ ions

2021 ◽  
Author(s):  
Shijia Sun ◽  
Qi Wei ◽  
Bing-Xuan Li ◽  
Xingjun Shi ◽  
feifei yuan ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Transmission Spectrum ◽  
Systematic Investigation ◽  
Solution Growth ◽  
Emission Characteristics ◽  
Multi Wavelength ◽  
Growth Method ◽  
Wavelength Emission ◽  
Spectrum Band ◽  
Top Seeded Solution Growth

The pure and Nd3+-doped YMgB5O10 (YMB, Nd:YMB) crystals were grown successfully by the top-seeded solution growth method with composite fluxes Li2O-B2O3-LiF. The systematic investigation of crystal structure, transmission spectrum, band...

Growth of Ti alloyed Nb3Sn crystals from Sn-Ti-Nb solutions by top seeded solution growth

1986 ◽  
Vol 78 (3) ◽  
pp. 567-570 ◽  
Author(s):  
T. Inoue ◽  
H. Komatsu ◽  
M. Shimizu ◽  
S. Tsunekawa ◽  
H. Takei
Keyword(s):  
Solution Growth ◽  
Top Seeded Solution Growth
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