The effect of crucible bottom deformation on the quality of Nd:GGG crystals grown by Czochralski method

2011 ◽  
Vol 46 (12) ◽  
pp. 1229-1234 ◽  
Author(s):  
H. Saeedi ◽  
M. Asadian ◽  
Sh. Enayati ◽  
N. Mirzaei ◽  
I. Mashayekhi Asl ◽  
...  
Keyword(s):  
Czochralski Method ◽  
Bottom Deformation ◽  
Crucible Bottom

Influences of MOS Device Characteristic under Different Oxygen-Dose Participations in the Silicon Substrate

2015 ◽  
Vol 656-657 ◽  
pp. 8-13
Author(s):  
Shen Li Chen ◽  
Tsung Shiung Lee ◽  
Yu Ting Huang
Keyword(s):  
Silicon Substrate ◽  
Czochralski Method ◽  
Silicon Substrates ◽  
Trap Charge ◽  
Substrate Quality ◽  
Mos Devices ◽  
Starting Point ◽  
Charge Characteristic ◽  
Mos Device

A silicon substrate is the starting point of producing the semiconductor component, so that the quality of semiconductor substrate is very important during the VLSI fabrication. In this paper, we will evaluate the influence of MOS device characteristics under different oxygen impurities in silicon substrates. In the course of silicon substrate pulling process by Czochralski method, the defect and impurity will be existed; the oxygen atom will be induced substrate dislocations and affected the substrate quality. In this work, different oxygen doses will be used in wafer to study the impacts on MOS CV curve characteristic, interface trap charge characteristic, ID-VDScurve, ID-VGScurve, and threshold voltage behaviors of MOS devices.

A Yb3+-doped NaY(WO4)2crystal grown by the Czochralski technique

2008 ◽  
Vol 41 (3) ◽  
pp. 584-591 ◽  
Author(s):  
Jiandong Fan ◽  
Huaijin Zhang ◽  
Wentao Yu ◽  
Haohai Yu ◽  
Jiyang Wang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Structure Refinement ◽  
Czochralski Method ◽  
Point Of View ◽  
X Ray Diffraction ◽  
X Ray ◽  
Growth Habits ◽  
The Relationship

A transparent Yb3+:NaY(WO4)2single crystal with dimensions of 30 mm (diameter) × 40 mm has been grown by the Czochralski method. The high crystalline quality of the as-grown Yb3+:NaY(WO4)2crystals was confirmed by high-resolution X-ray diffraction. The effective segregation coefficients of elemental Yb, Na, Y and W in Yb3+:NaY(WO4)2were measured using the X-ray fluorescence method. Powder and single-crystal X-ray diffraction data of NaYb0.05Y0.95(WO4)2are reported. The structure refinement shows that NaYb0.05Y0.95(WO4)2crystallizes in the tetragonal space groupI41/a, witha=b= 5.2039 (2),c= 11.2838 (9) Å, α = β = γ = 90°,V= 305.57 (3) Å3andZ= 2. A series of possible growth faces (hkl) were determined from the crystal lattice and symmetry according to the Bravais–Friedel Donnay–Harker theory, and the relationship among crystal structure, growth habits and crystal morphology is discussed. In addition, the thermal properties of the crystal, including the specific heat, thermal expansion, thermal diffusion and thermal conductivity, were carefully investigated. The anisotropy of the crystal thermal conductivities is explained from the point of view of the crystal structure.

Growing of bulk β-(Al x Ga1-x )2O3 crystals from the melt by Czochralski method and investigation of their structural and optical properties

2021 ◽  
Author(s):  
Dmitrii A. Zakgeim ◽  
Dmitrii Bauman ◽  
Dmitrii Yi. Panov ◽  
Vladislav A. Spiridonov ◽  
Arina Kremleva ◽  
...  
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Optical Transmission ◽  
Czochralski Method ◽  
Transmission Spectra ◽  
Structural And Optical Properties ◽  
X Ray ◽  
Al Content ◽  
Optical Transmission Spectra

Abstract Bulk (Al x Ga1-x )2O3 crystals with an Al fraction x in the range from 0.0 to 0.23 were successfully grown by the Czochralski method. An increase in the band gap from 4.7 eV to 5.1 eV with the rise of the Al content was demonstrated by analyzing optical transmission spectra. The crystal quality of the obtained samples was controlled by X-ray diffractometry. The appearance of crystal`s mosaic blockness was found for the Al fraction x above 0.05.

Investigation on the Morphologies of Dislocations in Sapphire Crystals

2011 ◽  
Vol 399-401 ◽  
pp. 954-957 ◽  
Author(s):  
Yu Sun ◽  
Hong Jian Chen ◽  
Wen Bo Yan ◽  
Cai Chi Liu
Keyword(s):  
Chemical Properties ◽  
Isosceles Triangle ◽  
Czochralski Method ◽  
Optical Systems ◽  
Sapphire Crystal ◽  
Vertical Bridgman ◽  
Sapphire Single Crystal ◽  
Corrosion Pits ◽  
Kyropoulos Method

Sapphire single crystal is widely used in a variety of modern applications from GaN-based LED to military optical systems because of its excellent combination of optical, mechanical, thermal and chemical properties. The dislocations affecting the quality of sapphire crystal were studied by chemical etching and optical microscopy in this paper. The experimental results showed that the dislocation corrosion pits of (11-20) plane in sapphire crystals grown by Kyropoulos method is diamond-shaped and (1-102) plane is isosceles triangle and the density of dislocations in samples grown by Czochralski method is about two orders of magnitude higher than that in samples grown by Vertical Bridgman method. The formation mechanism of defects and proposes was also discussed.

scholarly journals Выращивание объемных кристаллов оксида галлия из расплава методом Чохральского в кислородсодержащей атмосфере

2020 ◽  
Vol 46 (22) ◽  
pp. 43
Author(s):  
Д.А. Закгейм ◽  
Д.Ю. Панов ◽  
В.А. Спиридонов ◽  
А.В. Кремлева ◽  
А.М. Смирнов ◽  
...  
Keyword(s):  
Gallium Oxide ◽  
Optical Transmission ◽  
Czochralski Method ◽  
Transmission Spectra ◽  
X Ray ◽  
Growth Atmosphere ◽  
Optically Transparent ◽  
Optical Transmission Spectra ◽  
Oxide Crystals

This paper reports on successful experiments in growing beta-gallium oxide crystals using the Czochralski method. The influence of growth atmosphere composition on crystal quality of the material was studied. It is shown that to obtain high quality optically transparent crystals it is necessary to have about 5 vol.% oxygen in the growth atmosphere. X-ray structural analysis and investigation of optical transmission spectra of grown crystals are carried out.

The Study of Flower-Shaped Structure Dislocation in 4 Inch Germanium Single Crystal

2011 ◽  
Vol 685 ◽  
pp. 141-146 ◽  
Author(s):  
Miao Miao Li ◽  
Xiao Ping Su ◽  
De Shen Feng ◽  
Jian Long Zuo ◽  
Nan Li ◽  
...  
Keyword(s):  
Solar Cells ◽  
Dislocation Density ◽  
Single Crystal ◽  
Single Crystals ◽  
Czochralski Method ◽  
Structure Defects ◽  
Germanium Single Crystal ◽  
Low Dislocation Density ◽  
Dislocation Densities

As the key component of single junction GaAs/Ge solar cells and GaAs/Ge solar cells, the quality of germanium single crystal affects the properties of space solar cell directly. The dislocation of germanium single crystals is the main impact factor on solar cells efficiency. Through measuring dislocation densities in the different positions of 4 inch <100> germanium single crystals produced by Czochralski method, we found that flower-shaped structure dislocations pattern was mainly caused by the inclusions. This paper briefly analyzed dislocations produced by inclusions, chemical etching pits method. SEM and EDS measurement methods were also employed to study the flower-shaped structure defects. A germanium single crystal with low dislocation density was obtained and the special defects were almost eliminated. The germanium single crystal with low dislocation density (PV) was obtained, which could meet the requirement of the GaAs/Ge solar cells.

Thermal properties of monoclinic crystal Er3+:Yb3+:Ca4YO(BO3)3

2007 ◽  
Vol 40 (1) ◽  
pp. 125-132 ◽  
Author(s):  
W. W. Ge ◽  
H. J. Zhang ◽  
J. Y. Wang ◽  
M. H. Jiang ◽  
S. Q. Sun ◽  
...  
Keyword(s):  
Single Crystal ◽  
Czochralski Method ◽  
X Ray Diffraction ◽  
High Crystalline Quality ◽  
Monoclinic Crystal ◽  
Monoclinic System ◽  
X Ray ◽  
Rank Tensor ◽  
Co Doped

A large Er3+–Yb3+co-doped yttrium calcium oxoborate [Er3+:Yb3+:Ca4YO(BO3)3, abbreviated as Er:Yb:YCOB] single crystal, with dimensions of 2.5 cm in diameter and 9.0 cm in length, has been grown along the crystallographicbaxis by the Czochralski method. X-ray powder diffraction results show that the as-grown Er:Yb:YCOB crystal belongs to the monoclinic system with space groupCm; the unit-cell constants area= 8.085,b= 16.048,c= 3.528 Å and β = 101.11°. The high crystalline quality of the as-grown single crystal was confirmed by high-resolution X-ray diffraction, which showed the full width at half-maximum of the rocking curves to be less than 20 arcseconds on the (060) and (\overline 201) diffraction planes. The measurement and calculation of the symmetrical second-rank tensor for the monoclinic crystal are described in detail in this paper. The principal coefficients of thermal expansion of the as-grown Er:Yb:YCOB crystal are αI= 11.95 × 10−6 K−1, αII= 9.20 × 10−6 K−1and αIII= 18.93 × 10−6 K−1over the temperature range 303.15–873.15 K. The specific heat of the crystal is 725.6 J kg−1 K−1at 328.15 K. The principal thermal conductivity parameters areKI= 2.882 W m−1 K−1,KII= 2.687 W m−1 K−1andKIII= 2.692 W m−1 K−1at 328.15 K.

Immunoferritin localization of intracellular antigens in positively stained frozen sections

1978 ◽  
Vol 36 (2) ◽  
pp. 168-169
Author(s):  
K. T. Tokuyasu
Keyword(s):  
Surface Tension ◽  
Water Surface ◽  
Thin Layers ◽  
The Other ◽  
Positive Staining ◽  
Frozen Sections ◽  
The Past ◽  
Ultrathin Frozen Sections ◽  
Definition Of

During the past investigations of immunoferritin localization of intracellular antigens in ultrathin frozen sections, we found that the degree of negative staining required to delineate u1trastructural details was often too dense for the recognition of ferritin particles. The quality of positive staining of ultrathin frozen sections, on the other hand, has generally been far inferior to that attainable in conventional plastic embedded sections, particularly in the definition of membranes. As we discussed before, a main cause of this difficulty seemed to be the vulnerability of frozen sections to the damaging effects of air-water surface tension at the time of drying of the sections.Indeed, we found that the quality of positive staining is greatly improved when positively stained frozen sections are protected against the effects of surface tension by embedding them in thin layers of mechanically stable materials at the time of drying (unpublished).

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