Effect of crucible and crystal rotations on the solute distribution in large size sapphire crystals during Czochralski growth

2019 ◽  
Vol 130 ◽  
pp. 1307-1321
Author(s):  
Tran Phu Nguyen ◽  
Jyh-Chen Chen
Keyword(s):  
Solute Distribution ◽  
Czochralski Growth ◽  
Large Size

Large Size Czochralski Growth and Scintillation Properties of

2016 ◽  
Vol 63 (2) ◽  
pp. 443-447 ◽  
Author(s):  
Kei Kamada ◽  
Yasuhiro Shoji ◽  
Vladimir V. Kochurikhin ◽  
Aya Nagura ◽  
Satoshi Okumura ◽  
...  
Keyword(s):  
Czochralski Growth ◽  
Large Size

Czochralski Growth of Oxide Laser Crystals

1993 ◽  
Vol 329 ◽  
Author(s):  
Milan R. Koka
Keyword(s):  
Crystal Growth ◽  
Czochralski Growth ◽  
Solid State Lasers ◽  
Optically Pumped ◽  
Inorganic Oxides ◽  
Melting Temperatures ◽  
Individual Crystal ◽  
Large Size ◽  
Laser Crystals ◽  
Oxide Crystals

The most widely used active elements of optically pumped solid state lasers are crystals of inorganic oxides. Such oxide materials crystallasing in either garnet or corundum structures are prepared on industrial scale by the pulling technique known as Czochralski Crystal Growth. The description of the present state-of-the-art in Czochralski growth is described along with critical variables involved in growth of large size, high quality oxide crystals. The description of crystal growth of ruby, yttrium aluminum garnets, and titanium sapphire is presented. The effects of compositions, ambient atmospheres, crystal growth variables, and environmental conditions on individual crystal types are described. Suitability of the Czochralski technique for crystal growth of different oxides is discussed with emphasis on material properties such as phase diagram implication (congruency of melting), melting temperatures, crucible materials, effects of doping ions, and high temperature melt chemistry.

scholarly journals Effect of Internal Radiation on Process Parameters in the Global Simulation of Growing Large-Size Bulk β-Ga2O3 Single Crystals with the Czochralski Method

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 763
Author(s):  
Xia Tang ◽  
Botao Liu ◽  
Yue Yu ◽  
Botao Song ◽  
Pengfei Han ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Single Crystal ◽  
Process Parameters ◽  
Czochralski Method ◽  
Surface Radiation ◽  
Czochralski Growth ◽  
Internal Radiation ◽  
System A ◽  
Large Size ◽  
Growth System

As a crystal grows, the temperature distribution of the crystal and melt will change. It is necessary to study the dynamic process of single-crystal growth. Due to the relatively low crystallization rates used in the industrial Czochralski growth system, a steady state is used to compute the temperature distribution and melt flow. A two-dimensional axisymmetric model of the whole Czochralski furnace was established. The dynamic growth process of large-size bulk β-Ga2O3 single crystal using the Czochralski method has been numerically analyzed with the parameter sweep method. In this paper, two cases of internal radiation and no internal radiation were compared to study the effect of radiation on the process parameters. The temperature distribution of the furnace, the temperature field, and the flow field of the melt was calculated. The temperature, the temperature gradient of the crystal, the temperature at the bottom of the crucible, and the heater power were studied for the crystals grown in the two cases of radiation. The results obtained in this study clearly show that the loss calculated by including the internal radiation is higher compared to that including the surface radiation.

Effect of crucible and crystal rotations on the convexity and the thermal stress in large size sapphire crystals during Czochralski growth

2017 ◽  
Vol 468 ◽  
pp. 514-525 ◽  
Author(s):  
Tran Phu Nguyen ◽  
Yao-Te Hsieh ◽  
Jyh-Chen Chen ◽  
Chieh Hu ◽  
Huy Bich Nguyen
Keyword(s):  
Thermal Stress ◽  
Czochralski Growth ◽  
Large Size

scholarly journals Czochralski growth of mixed cubic sesquioxide crystals in the ternary system Lu2O3–Sc2O3–Y2O3

2021 ◽  
Vol 77 (4) ◽  
Author(s):  
Christian Kränkel ◽  
Anastasia Uvarova ◽  
Émile Haurat ◽  
Lena Hülshoff ◽  
Mario Brützam ◽  
...  
Keyword(s):  
Ternary System ◽  
Czochralski Method ◽  
Optical Quality ◽  
Czochralski Growth ◽  
High Optical Quality ◽  
Melting Temperatures ◽  
Large Size ◽  
Host Materials ◽  
Thermal Investigations ◽  
First Time

Cubic rare-earth sesquioxide crystals are strongly demanded host materials for high power lasers, but due to their high melting points investigations on their thermodynamics and the growth of large-size crystals of high optical quality remain a challenge. Detailed thermal investigations of the ternary system Lu2O3–Sc2O3–Y2O3 revealing a large range of compositions with melting temperatures below 2200°C and a minimum of 2053°C for the composition (Sc0.45Y0.55)2O3 are presented. These reduced temperatures enable for the first time the growth of high optical quality mixed sesquioxide crystals with disordered structure by the conventional Czochralski method from iridium crucibles. An (Er0.07Sc0.50Y0.43)2O3 crystal is successfully grown and characterized with respect to its crystallographic properties as well as its composition, thermal conductivity and optical absorption in the 1 µm range.

Coherency loss in γ' precipitates in nickel-base superalloy

1983 ◽  
Vol 41 ◽  
pp. 244-245
Author(s):  
R. A. Ricks ◽  
Angus J. Porter
Keyword(s):  
Lattice Mismatch ◽  
Lattice Parameter ◽  
Nickel Base Superalloy ◽  
Large Size ◽  
The Matrix ◽  
Nimonic 80A ◽  
Interfacial Dislocations ◽  
Nickel Base ◽  
Coherency Loss ◽  
Nimonic 115

During a recent investigation concerning the growth of γ' precipitates in nickel-base superalloys it was observed that the sign of the lattice mismatch between the coherent particles and the matrix (γ) was important in determining the ease with which matrix dislocations could be incorporated into the interface to relieve coherency strains. Thus alloys with a negative misfit (ie. the γ' lattice parameter was smaller than the matrix) could lose coherency easily and γ/γ' interfaces would exhibit regularly spaced networks of dislocations, as shown in figure 1 for the case of Nimonic 115 (misfit = -0.15%). In contrast, γ' particles in alloys with a positive misfit could grow to a large size and not show any such dislocation arrangements in the interface, thus indicating that coherency had not been lost. Figure 2 depicts a large γ' precipitate in Nimonic 80A (misfit = +0.32%) showing few interfacial dislocations.

TEM characterization of silicon epitaxial layer grown on Si-TaS2, eutectic composites

1991 ◽  
Vol 49 ◽  
pp. 802-803
Author(s):  
C.M. Sung ◽  
M. Levinson ◽  
M. Tabasky ◽  
K. Ostreicher ◽  
B.M. Ditchek
Keyword(s):  
Substrate Surface ◽  
Bulk Sample ◽  
Surface Cleaning ◽  
Native Oxide ◽  
Czochralski Growth ◽  
Ion Milling ◽  
Cross Sectional ◽  
Cleaning Methods ◽  
Field Emission Cathodes

Directionally solidified Si/TaSi2 eutectic composites for the development of electronic devices (e.g. photodiodes and field-emission cathodes) were made using a Czochralski growth technique. High quality epitaxial growth of silicon on the eutectic composite substrates requires a clean silicon substrate surface prior to the growth process. Hence a preepitaxial surface cleaning step is highly desirable. The purpose of this paper is to investigate the effect of surface cleaning methods on the epilayer/substrate interface and the characterization of silicon epilayers grown on Si/TaSi2 substrates by TEM.Wafers were cut normal to the <111> growth axis of the silicon matrix from an approximately 1 cm diameter Si/TaSi2 composite boule. Four pre-treatments were employed to remove native oxide and other contaminants: 1) No treatment, 2) HF only; 3) HC1 only; and 4) both HF and HCl. The cross-sectional specimens for TEM study were prepared by cutting the bulk sample into sheets perpendicular to the TaSi2 fiber axes. The material was then prepared in the usual manner to produce samples having a thickness of 10μm. The final step was ion milling in Ar+ until breakthrough occurred. The TEM samples were then analyzed at 120 keV using the Philips EM400T.

Automatic analysis of Kikuchi diffraction patterns

1994 ◽  
Vol 52 ◽  
pp. 900-901
Author(s):  
H. Weiland ◽  
D. P. Field
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Spatial Resolution ◽  
Relevant Information ◽  
Crystalline Materials ◽  
Large Size ◽  
Transmission Electron ◽  
New Type ◽  
Diffraction Patterns ◽  
Orientation Determination

Recent advances in the automatic indexing of backscatter Kikuchi diffraction patterns on the scanning electron microscope (SEM) has resulted in the development of a new type of microscopy. The ability to obtain statistically relevant information on the spatial distribution of crystallite orientations is giving rise to new insight into polycrystalline microstructures and their relation to materials properties. A limitation of the technique in the SEM is that the spatial resolution of the measurement is restricted by the relatively large size of the electron beam in relation to various microstructural features. Typically the spatial resolution in the SEM is limited to about half a micron or greater. Heavily worked structures exhibit microstructural features much finer than this and require resolution on the order of nanometers for accurate characterization. Transmission electron microscope (TEM) techniques offer sufficient resolution to investigate heavily worked crystalline materials.Crystal lattice orientation determination from Kikuchi diffraction patterns in the TEM (Figure 1) requires knowledge of the relative positions of at least three non-parallel Kikuchi line pairs in relation to the crystallite and the electron beam.

Immunoprobe localization in mammalian embryos

1990 ◽  
Vol 48 (3) ◽  
pp. 32-33
Author(s):  
Patricia G. Calarco ◽  
Margaret C. Siebert
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Thin Sections ◽  
Relative Lack ◽  
Large Size ◽  
Mammalian Embryos ◽  
Antigen Localization ◽  
Difficult Challenge ◽  
Lowicryl K4m ◽  
Fertilized Egg

Visualization of preimplantation mammalian embryos by electron microscopy is difficult due to the large size of the ircells, their relative lack of internal structure, and their highly hydrated cytoplasm. For example, the fertilized egg of the mouse is a single cell of approximately 75μ in diameter with little organized cytoskelet on and apaucity ofor ganelles such as endoplasmic reticulum (ER) and Golgi material. Thus, techniques that work well on tissues or cell lines are often not adaptable to embryos at either the LM or EM level.Over several years we have perfected techniques for visualization of mammalian embryos by LM and TEM, SEM and for the pre-embedding localization of antigens. Post-embedding antigenlocalization in thin sections of mouse oocytes and embryos has presented a more difficult challenge and has been explored in LR White, LR Gold, soft EPON (after etching of sections), and Lowicryl K4M. To date, antigen localization has only been achieved in Lowicryl-embedded material, although even with polymerization at-40°C, the small ER vesicles characteristic of embryos are unrecognizable.

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