Influences of Solution Flow and Lateral Temperature Distribution on Surface Morphology in Solution Growth of SiC

The influences of solution flow and lateral temperature distribution on the surface morphology of the 4H-SiC single crystal grown from solution was investigated. A flat surface region was enlarged by the seed-rotation rate. The solution flow simulation indicated that the higher rotation rate made the outward solution flow ordered beneath the solution surface. Such a solution flow was thought to be effective to enlarge the flat region of growth front. Furthermore, a full-flat surface was obtained with a hollow-type graphite rod at a seed-rotation rate of 60 min-1. The simulated results of temperature distribution showed the hollow-type graphite rod reduced the lateral temperature gradient at the SiC-solution interface. The ordered solution flow and the small temperature gradient at the growth front were found to be effective to make the growth front flat in the solution-growth method.

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Effect of Radiation in Solid during SiC Sublimation Growth

MRS Proceedings ◽

10.1557/proc-0911-b01-02 ◽

2006 ◽

Vol 911 ◽

Cited By ~ 1

Author(s):

Shin-ichi Nishizawa ◽

Shin-ichi Nakashima ◽

Tomohisa Kato

Keyword(s):

Thermal Stress ◽

Temperature Distribution ◽

Temperature Gradient ◽

Absorption Coefficient ◽

Doping Concentration ◽

Grown Crystal ◽

Growth Front ◽

Growth Features ◽

Sublimation Growth ◽

Front Temperature

AbstractThe effect of infrared absorption on SiC sublimation growth was numerically investigated. At first, absorption coefficient was estimated as function of doping concentration. Then temperature distribution inside a crucible was numerically analyzed with taking account of absorption in growing crystal. It was pointed out that temperature distribution in a growing crystal strongly depends on absorption coefficient, i.e. doping concentration. As increasing the absorption coefficient, the growth front temperature and temperature gradient inside a growing crystal increase. It might cause large thermal stress and affect the grown crystal quality. This agrees well with growth features in experiment. The growth condition should be determined with taking account of absorption coefficient, i.e. doping concentration.

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Effect of Solution Drift on Crystalline Morphology in the Solution Growth of Off-Axis 4H-SiC Crystals

Materials Science Forum ◽

10.4028/www.scientific.net/msf.858.65 ◽

2016 ◽

Vol 858 ◽

pp. 65-68

Author(s):

Takashi Kato ◽

Kazuhiko Kusunoki ◽

Kazuaki Seki ◽

Nobuhiro Okada ◽

Kazuhito Kamei

Keyword(s):

Surface Morphology ◽

Flow Direction ◽

Solute Concentration ◽

The Other ◽

Solution Growth ◽

Morphological Stability ◽

Crystalline Morphology ◽

Solution Flow ◽

Step Flow ◽

Flow Directions

We investigated the effect of the solution flow on crystalline morphology in the off-axis 4H-SiC solution growth. In particular, we focused on the relation between the Si solution flow and step flow directions. In step parallel flow in which the solution drifted transversely to the step flow direction of the off-axis substrate, it was possible to attain a better surface morphology than in the flow in which the solution drifted toward the other direction. Furthermore, it was found that the surface morphology was found to be improved as the solution flow velocity increased. These improvements in the morphological stability are presumed to be caused by aligning the solute concentration fluctuation along the steps.

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

Materials Science Forum ◽

10.4028/www.scientific.net/msf.821-823.18 ◽

2015 ◽

Vol 821-823 ◽

pp. 18-21 ◽

Cited By ~ 3

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 ◽

Temperature Field Boundary Conditions and Lateral Temperature Gradient Effect on a PC Box-Girder Bridge Based on Real-Time Solar Radiation and Spatial Temperature Monitoring

Sensors ◽

10.3390/s20185261 ◽

2020 ◽

Vol 20 (18) ◽

pp. 5261

Author(s):

Xiao Lei ◽

Xutao Fan ◽

Hanwan Jiang ◽

Kunning Zhu ◽

Hanyu Zhan

Keyword(s):

Temperature Distribution ◽

Temperature Gradient ◽

Solar Radiation ◽

Prediction Model ◽

Monitoring Data ◽

Radiation Boundary Condition ◽

Box Girder ◽

Box Girder Bridge ◽

Girder Bridge ◽

Lateral Temperature

Climate change could impose great influence on infrastructures. Previous studies have shown that solar radiation is one of the most important factors causing the change in temperature distribution in bridges. The current temperature distribution models developed in the past are mainly based on the meteorological data from the nearest weather station, empirical formulas, or the testing data from model tests. In this study, a five-span continuous Prestressed-concrete box-girder bridge was instrumented with pyranometers, anemometers, strain gauges, displacement gauges, and temperature sensors on the top and bottom slabs and webs to measure the solar radiation, wind speeds, strain, displacement, and surface temperatures, respectively. The continuously monitoring data between May 2019 and May 2020 was used to study the temperature distributions caused by solar radiation. A maximum positive lateral temperature gradient prediction model has been developed based on the solar radiation data analysis. Then, the solar radiation boundary condition obtained from the monitoring data and the lateral temperature gradient prediction model were utilized to compute the tensile stresses in the longitudinal and transverse directions. It was demonstrated in this study that the tensile stress caused by the lateral temperature gradient was so significant that it cannot be ignored in structural design.

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Stable Growth of 4H-SiC Single Polytype by Controlling the Surface Morphology Using a Temperature Gradient in Solution Growth

Materials Science Forum ◽

10.4028/www.scientific.net/msf.717-720.53 ◽

2012 ◽

Vol 717-720 ◽

pp. 53-56 ◽

Cited By ~ 2

Author(s):

Yuji Yamamoto ◽

Kazuaki Seki ◽

Shigeta Kozawa ◽

Alexander ◽

S. Harada ◽

...

Keyword(s):

Temperature Gradient ◽

Surface Morphology ◽

Solution Growth ◽

Grown Layer ◽

Stable Growth

We introduce a method to grow 4H-SiC single polytype stably by controlling the surface morphology. The polytype transition on on-axis 4H-SiC C-face was investigated from a viewpoint of surface morphology of grown layers. At the area where several hillock-like structures grew adjacently, the polytype transition from 4H-SiC to 6H-SiC or 15R-SiC often occurred. Therefore, we tried a modified seeded method to suppress the formation of hillock-like structures. As a result, the hillock-like structure on the grown layer was dramatically reduced. Moreover, the ratio of 4H-SiC polytype to the whole grown surface was increased to be almost 100%.

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Effect of Forced Convection by Crucible Design in Solution Growth of SiC Single Crystal

Materials Science Forum ◽

10.4028/www.scientific.net/msf.821-823.22 ◽

2015 ◽

Vol 821-823 ◽

pp. 22-25 ◽

Cited By ~ 2

Author(s):

Kazuhisa Kurashige ◽

Masahiro Aoshima ◽

Koichi Takei ◽

Kuniharu Fujii ◽

Masahiko Hiratani ◽

...

Keyword(s):

Growth Rate ◽

Single Crystal ◽

Forced Convection ◽

Centrifugal Force ◽

Rotation Rate ◽

Growth Front ◽

Solution Growth

In this paper, we will discuss how to cope with the smoother growth front and higher growth rate by the forced convection. When the rotation rate of the upper part of the solution is different from that of the lower part in the crucible, the centrifugal force of the upper part is different from that of the lower part. As a result, a forced convection occurs in the solution. This kind of convection was achieved with accelerating/decelerating rotation of crucible and a plate fixed on the bottom of the crucible. By optimizing conditions of rotation program patterns and the crucible design for the forced convection, the growth rate could almost be doubled while maintaining smooth morphology.

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Lattice constant, bandgap, thickness, and surface morphology of InGaAsP-InP layers grown by step-cooling, equilibrium-cooling, supercooling and two-phase-solution growth techniques

Journal of Electronic Materials ◽

10.1007/bf02670849 ◽

1980 ◽

Vol 9 (2) ◽

pp. 241-280 ◽

Cited By ~ 56

Author(s):

M. Feng ◽

L. W. Cook ◽

M. M. Tashima ◽

G. E. Stillman

Keyword(s):

Surface Morphology ◽

Lattice Constant ◽

Solution Growth ◽

Two Phase ◽

Phase Solution

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Temperature log simulations in high-enthalpy boreholes

Geothermal Energy ◽

10.1186/s40517-019-0149-0 ◽

2019 ◽

Vol 7 (1) ◽

Cited By ~ 2

Author(s):

Jia Wang ◽

Fabian Nitschke ◽

Maziar Gholami Korzani ◽

Thomas Kohl

Keyword(s):

Heat Transfer ◽

Temperature Distribution ◽

Temperature Gradient ◽

Flow Rate ◽

Fluid Loss ◽

Flow Conditions ◽

Flow Rates ◽

High Enthalpy ◽

Fluid Losses ◽

Lateral Heat

Abstract Temperature logs have important applications in the geothermal industry such as the estimation of the static formation temperature (SFT) and the characterization of fluid loss from a borehole. However, the temperature distribution of the wellbore relies on various factors such as wellbore flow conditions, fluid losses, well layout, heat transfer mechanics within the fluid as well as between the wellbore and the surrounding rock formation, etc. In this context, the numerical approach presented in this paper is applied to investigate the influencing parameters/uncertainties in the interpretation of borehole logging data. To this end, synthetic temperature logs representing different well operation conditions were numerically generated using our newly developed wellbore simulator. Our models account for several complex operation scenarios resulting from the requirements of high-enthalpy wells where different flow conditions, such as mud injection with- and without fluid loss and shut-in, occur in the drill string and the annulus. The simulation results reveal that free convective heat transfer plays an important role in the earlier evolution of the shut-in-time temperature; high accuracy SFT estimation is only possible when long-term shut-in measurements are used. Two other simulation scenarios for a well under injection conditions show that applying simple temperature correction methods on the non-shut-in temperature data could lead to large errors for SFT estimation even at very low injection flow rates. Furthermore, the magnitude of the temperature gradient increase depends on the flow rate, the percentage of fluid loss and the lateral heat transfer between the fluid and the rock formation. As indicated by this study, under low fluid losses (< 30%) or relatively higher flow rates (> 20 L/s), the impact of flow rate and the lateral heat transfer on the temperature gradient increase can be ignored. These results provide insights on the key factors influencing the well temperature distribution, which are important for the choice of the drilling data to estimate SFT and the design of the inverse modeling scheme in future studies to determine an accurate SFT profile for the high-enthalpy geothermal environment.

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