scholarly journals Homogenization of Radial Temperature by a Tungsten Sink in Sublimation Growth of 45 mm AlN Single Crystal

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5553
Author(s):  
Yue Yu ◽  
Botao Liu ◽  
Xia Tang ◽  
Sheng Liu ◽  
Bing Gao
Keyword(s):  
Thermal Stress ◽  
Crystal Growth ◽  
Heat Exchange ◽  
Single Crystal ◽  
Numerical Experiments ◽  
Radial Temperature Gradient ◽  
Radial Temperature ◽  
Large Size ◽  
Sublimation Growth

To reduce the thermal stress during the sublimation growth of 45 mm AlN single crystal, a tungsten sink was put on the top of the crucible lid. Numerical experiments showed that the radial temperature gradient was reduced due to the homogenization effect on temperature as a result of the sink. Therefore, this simple tungsten sink method has the potential to grow large-size AlN ingots with fewer cracks. It also reveals that enhancing the heat exchange of the crucible lid is an effective way to improve the quality of crystal growth.

The Effect of Modified Crucible Design and Seed Attachment on SiC Crystal Grown by PVT

2013 ◽  
Vol 740-742 ◽  
pp. 77-80
Author(s):  
Jung Young Jung ◽  
Sang Il Lee ◽  
Mi Seon Park ◽  
Doe Hyung Lee ◽  
Hee Tae Lee ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Temperature Gradient ◽  
Single Crystals ◽  
Crystal Quality ◽  
Full Width ◽  
Half Maximum ◽  
Radial Temperature Gradient ◽  
Radial Temperature ◽  
Better Than

The present research was focused to investigate the effect of internal crucible design that influenced the 4H-SiC crystal growth onto a 6H-SiC seed by PVT method. The crucible design was modified to produce a uniform radial temperature gradient in the growth cell. The seed attachment was also modified with a use of polycrystalline SiC plate. The crystal quality of 4H-SiC single crystals grown in modified crucible and grown with modified seed attachment was revealed to be better than that of crystal grown in conventional crucible. The full width at half maximum (FWHM) values of grown SiC crystals in the conventional crucible, the modified seed attachment and the modified crucible were 285 arcsec, 134 arcsec and 128 arcsec, respectively. The micropipe density (MPD) of grown SiC crystals in the conventional crucible, the modified seed attachment and the modified crucible were 101ea/cm^2, 81ea/cm^2 and 42ea/cm^2, respectively.

Effect of Marangoni Convection on InSb Single Crystal Growth by Horizontal Bridgman Method

2001 ◽  
Vol 692 ◽  
Author(s):  
K. Kodera ◽  
A. Kinoshita ◽  
K. Arafune ◽  
Y. Nakae ◽  
A. Hirata
Keyword(s):  
Crystal Growth ◽  
Binary System ◽  
Temperature Gradient ◽  
Single Crystal ◽  
Grown Crystal ◽  
Marangoni Convection ◽  
Single Crystal Growth ◽  
Control Technique ◽  
Growth System

AbstractIt is necessary to clarify the effect of Marangoni convection on single crystal growth from a melt in order to improve the quality of the grown crystal. Particularly, the deviation of crystalmelt (C-M) interface from a planar shape is a major problem because it may deteriorate the quality of the grown crystal. In this paper, we investigated the effect of thermal and solutal Marangoni convection on C-M interface shape in an In-Sb binary system by the horizontal Bridgman (HB) method. The C-M interface concavity strongly depends on the cooling rate and the temperature gradient under uniform concentration distribution conditions in the melt. A large concavity was observed at low cooling rates and high temperature gradient conditions. The concavity was found to be caused by thermal Marangoni convection, by taking Péclet number into account. Then, we varied the composition of the In-Sb binary system to induce solutal Marangoni convection intentionally. The C-M interface was kept planar in case solutal Marangoni convection occurred in the direction opposite to the thermal one. Therefore, we believe that the utilization of solutal Marangoni convection will be a new control technique to make the C-M interface planar for the HB system. From these results, it was clarified that Marangoni convection plays a significant role in the HB crystal growth system.

Large-size TlBr single crystal growth and defect study

2018 ◽  
Vol 487 ◽  
pp. 8-11 ◽  
Author(s):  
Mingzhi Zhang ◽  
Zhiping Zheng ◽  
Zheng Chen ◽  
Sen Zhang ◽  
Wei Luo ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Single Crystal ◽  
Single Crystal Growth ◽  
Large Size

Analysis to Reduce Thermal Stress in Oxide Single Crystal During Czochralski Growth

2004 ◽  
Author(s):  
Shigeki Hirasawa ◽  
Hiroyuki Ishibashi ◽  
Kazuhisa Kurashige ◽  
Akihiro Gunji
Keyword(s):  
Heat Transfer ◽  
Thermal Stress ◽  
Temperature Distribution ◽  
Thermal Radiation ◽  
Single Crystal ◽  
Radiation Heat Transfer ◽  
Heat Transfer Analysis ◽  
Czochralski Growth ◽  
Radiation Heat ◽  
Radial Temperature

Temperature distributions and thermal stress distributions in a semi-transparent GSO crystal during Czochralski (CZ) single crystal growth were numerically investigated by thermal radiation heat transfer analysis and anisotropy stress analysis. As GSO has special optical properties, such as semi-transparency at a wavelength shorter than 4.5 μm, thermal radiation heat transfer was calculated by the Monte Carlo method. These calculations showed that thermal stress is caused by the radial temperature distribution on the outside of the upper part of the crystal. To reduce this temperature distribution, the following three manufacturing conditions were found to be effective: use a sharp taper angle of the crystal, install a lid to the top of the insulator, and install a ring around the tapered part of the crystal.

scholarly journals Simulation and Experiment for Growth of High-Quality and Large-Size AlN Seed Crystals by Spontaneous Nucleation

Sensors ◽  
2020 ◽  
Vol 20 (14) ◽  
pp. 3939
Author(s):  
Zuoyan Qin ◽  
Wenhao Chen ◽  
Danxia Deng ◽  
Zhenhua Sun ◽  
Baikui Li ◽  
...  
Keyword(s):  
Temperature Gradient ◽  
Single Crystal ◽  
Growth Surface ◽  
Inversion Method ◽  
High Quality ◽  
Radial Temperature ◽  
Heater Power ◽  
Seed Crystals ◽  
Spontaneous Nucleation ◽  
Large Size

Seed crystals are the prerequisite for the growth of high quality and large size aluminum nitride (AlN) single crystal boules. The physical vapor transport (PVT) method is adopted to grow AlN seed crystal. However, this method is not available in nature. Herein, the temperature field distribution in the PVT furnace was simulated using the numerical analysis method to obtain free-standing and large-size seeds. The theoretical studies indicate that the temperature distribution in the crucible is related to the crucible height. According to the theory of growth dynamics and growth surface dynamics, the optimal thermal distribution was achieved through the design of a specific crucible structure, which is determined by the ratio of top-heater power to main-heater power. Moreover, in our experiment, a sole AlN single crystal seed with a length of 12 mm was obtained on the tungsten (W) substrate. The low axial temperature gradient between material source and substrate can decrease the nucleation rate and growth rate, and the high radial temperature gradient of the substrate can promote the expansion of crystal size. Additionally, the crystallinity of the crystals grown under different thermal field conditions are analyzed and compared. The Raman results manifest the superiority of the thermal inversion method in the growth of high quality AlN single crystal.

Crystal growth, optical, thermal and piezoelectric properties of HoCa4O(BO3)3 crystal

CrystEngComm ◽  
2021 ◽  
Author(s):  
Pingzhang Yu ◽  
Xiaobo Pan ◽  
guangda wu ◽  
Yanqing Liu ◽  
Fapeng Yu ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Single Crystal ◽  
Piezoelectric Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Parameters ◽  
Large Size

Large size HoCa4O(BO3)3 (HoCOB) crystal was successfully grown by the Czochralski (Cz) method. Through single-crystal X-ray diffraction the cell parameters were determined to be a = 8.090(3) Å, b =...

Large size SBN single crystal growth by the resistance-heating Czochralski technique using crucible-base cooling

2001 ◽  
Vol 229 (1-4) ◽  
pp. 217-222 ◽  
Author(s):  
E Kubota ◽  
H Yamazaki ◽  
M Ono ◽  
M Sasaura ◽  
S Yagi ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Single Crystal ◽  
Single Crystal Growth ◽  
Resistance Heating ◽  
Czochralski Technique ◽  
Large Size

The photoelastic determination of thermal stress concentrations in grooved cylinders with a radial temperature gradient

1979 ◽  
Vol 14 (3) ◽  
pp. 95-102 ◽  
Author(s):  
F A Khayyat ◽  
P Stanley
Keyword(s):  
Thermal Stress ◽  
Steady State ◽  
Temperature Gradient ◽  
Scattered Light ◽  
Radial Temperature Gradient ◽  
Stress Concentrations ◽  
Radial Temperature ◽  
Hollow Cylinders ◽  
Non Destructive

A non-destructive photoelastic technique, requiring integrated retardation and scattered-light measurements, is used for the determination of thermal stress concentrations in hollow cylinders with (i) an internal and (ii) an external curcumferential groove, subjected to a steady-state radial temperature gradient.

Modeling of Fine Annealing of Large Size Optical Glass

2013 ◽  
Author(s):  
Yefeng Ma ◽  
Nan Wu ◽  
Lihua Li ◽  
Song Zhang ◽  
Lili Zheng ◽  
...  
Keyword(s):  
Heat Exchange ◽  
Temperature Distribution ◽  
Temperature Difference ◽  
Optical Glass ◽  
Maximum Temperature ◽  
Glass Temperature ◽  
Insulation Layer ◽  
Large Size ◽  
Fine Annealing

Large size optical glass has attracted much attention due to its applications in large optical devices. Due to stringent requirement in applications, extra thermal treatment should be investigated to increase the quality of product. During fine annealing, glass temperature is crucial for final quality of optical glass as a result of its influence on thermal stress and optical homogeneity. To ensure a high performance, temperature distribution in the glass should be homogeneous and symmetric, and maximum temperature difference is expected to be small. This paper proposed two approaches to improve the glass temperature uniformity during fine annealing. Firstly, the glass blocks are packaged with heat exchange blocks on the top and bottom surfaces and insulation layer on the side. Thickness of layers and materials usage are investigated. Simulation results show that the homogeneity and symmetry of glass temperature distribution can be improved. Temperature difference in the horizontal direction can be further reduced in the case of 10mm copper heat exchange block together with 50mm insulation layer. Secondly, a muffle apparatus is utilized and symmetry of temperature distribution can be improved. Furthermore, above two approaches can be combined. Knowledge learned in this work can be used to guide industrial fine annealing process to reduce the stress level and improve the symmetric of residual stress.

Sign in / Sign up

Export Citation Format

Share Document