A liquid-bridge model for the float-zone processing of materials

1985 ◽  
Vol 81 (11) ◽  
pp. 2787 ◽  
Author(s):  
Ernest A. Boucher ◽  
Michael J. B. Evans
Keyword(s):  
Liquid Bridge ◽  
Float Zone ◽  
Bridge Model

The effect of liquid bridge model details on the dynamics of wet fluidized beds

AIChE Journal ◽  
2017 ◽  
Vol 64 (2) ◽  
pp. 437-456 ◽  
Author(s):  
Mingqiu Wu ◽  
Johannes G. Khinast ◽  
Stefan Radl
Keyword(s):  
Liquid Bridge ◽  
Fluidized Beds ◽  
Bridge Model

Deformation of a Thermocapillary Driven Liquid Bridge

2005 ◽  
Author(s):  
Brent C. Houchens ◽  
John S. Walker
Keyword(s):  
Free Surface ◽  
Liquid Bridge ◽  
Numerical Models ◽  
Dynamic Pressure ◽  
Surface Shape ◽  
Leading Order ◽  
Advantages And Disadvantages ◽  
Float Zone ◽  
Free Surface Shape ◽  
Physical Insight

Predicting the free-surface shape of a liquid bridge has been the focus of several recent models of containerless semiconductor crystal-growth methods, such as float-zone processing. We wish to sort out the discrepancies in the predictions of the numerical models by investigating the physics of a simplified system, the half-zone in microgravity. In the absence of gravity, the deformation of the free surface is small. Therefore, we first calculate the flow for a cylindrical melt region, corresponding to a large reference surface tension. This problem is well benchmarked, and the results are in nearly universal agreement. We then investigate a small perturbation of the free-surface shape using the flow calculated for the undeformed liquid bridge. Applying asymptotic expansions, we can predict the leading order of the free-surface velocities and deformation. In this formulation, it is easy to understand the relevance of each term, including the dynamic pressure variation. This solution is also more efficient than the numerical schemes that iterate between the shape of the free surface and the associated flow field. Furthermore, it provides physical insight that is difficult to extract from a purely numerical solution. Conversely, it is an approximation and therefore neglects terms of importance to a highly deformed free surface. Where possible, we will compare the leading-order free-surface shape to that predicted by numerical models, and discuss the advantages and disadvantages of this technique.

A Numerical Study of Effect of Liquid Encapsulation on Thermocapillary Convection in Liquid Bridge

2004 ◽  
Author(s):  
Lan Peng ◽  
Dan-Ling Zeng ◽  
You-Rong Li
Keyword(s):  
Numerical Simulation ◽  
Crystal Growth ◽  
Liquid Bridge ◽  
Function Method ◽  
Thermocapillary Convection ◽  
Numerical Study ◽  
Flow Profile ◽  
Float Zone ◽  
Physical And Mathematical Models

The physical and mathematical models of the thermocapillary convection in liquid bridge with liquid encapsulation are established in the present paper. A numerical simulation of the thermocapillary convection in liquid bridge with liquid encapsulation is performed by employed vorticity-stream function method and the Alternative Direction Implicit scheme in finite difference. The distribution of temperature and flow in liquid columns is then obtained. It is verified that liquid encapsulation can reduce the thermocapillary convection in liquid bridge and can improve the quality of crystal growth in float zone. The influence law of the thickness of liquid encapsulation on the thermocapillary convection in liquid bridge is obtained, the more thickness of liquid encapsulation decreases, the more the thermocapillary convection in the inner liquid and the outer liquid diminishes. It is found that the flow profile of two liquid columns is much more complex than that of single liquid column.

Examination of Extra Electron Diffraction Spots Observed in Deuterium-Irradiated Silicon by Using Parallel Electron Beam Illumination

1990 ◽  
Vol 48 (2) ◽  
pp. 490-491
Author(s):  
Ryuichiro Oshima ◽  
Shoichiro Honda ◽  
Tetsuo Tanabe
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Silicon Single Crystal ◽  
Mixed Solution ◽  
Parallel Beam ◽  
Defect Clusters ◽  
Float Zone ◽  
Transmission Electron ◽  
Extra Electron ◽  
Diffraction Patterns

In order to examine the origin of extra diffraction spots and streaks observed in selected area diffraction patterns of deuterium irradiated silicon, systematic diffraction experiments have been carried out by using parallel beam illumination.Disc specimens 3mm in diameter and 0.5mm thick were prepared from a float zone silicon single crystal(B doped, 7kΩm), and were chemically thinned in a mixed solution of nitric acid and hydrogen fluoride to make a small hole at the center for transmission electron microscopy. The pre-thinned samples were irradiated with deuterium ions at temperatures between 300-673K at 20keV to a dose of 1022ions/m2, and induced lattice defects were examined under a JEOL 200CX electron microscope operated at 160kV.No indication of formation of amorphous was obtained in the present experiments. Figure 1 shows an example of defects induced by irradiation at 300K with a dose of 2xl021ions/m2. A large number of defect clusters are seen in the micrograph.

Morphology and development of flow-pattern defect with extended nonagitated Secco etching

1994 ◽  
Vol 52 ◽  
pp. 868-869
Author(s):  
Y. Pan
Keyword(s):  
Flow Pattern ◽  
Silicon Crystal ◽  
Gate Oxide ◽  
Crystal Growth Rate ◽  
Etch Depth ◽  
Force Microscopy ◽  
Etch Pit ◽  
Float Zone ◽  
Atomic Force ◽  
Multiple Step

The D defect, which causes the degradation of gate oxide integrities (GOI), can be revealed by Secco etching as flow pattern defect (FPD) in both float zone (FZ) and Czochralski (Cz) silicon crystal or as crystal originated particles (COP) by a multiple-step SC-1 cleaning process. By decreasing the crystal growth rate or high temperature annealing, the FPD density can be reduced, while the D defectsize increased. During the etching, the FPD surface density and etch pit size (FPD #1) increased withthe etch depth, while the wedge shaped contours do not change their positions and curvatures (FIG.l).In this paper, with atomic force microscopy (AFM), a simple model for FPD morphology by non-crystallographic preferential etching, such as Secco etching, was established.One sample wafer (FPD #2) was Secco etched with surface removed by 4 μm (FIG.2). The cross section view shows the FPD has a circular saucer pit and the wedge contours are actually the side surfaces of a terrace structure with very small slopes. Note that the scale in z direction is purposely enhanced in the AFM images. The pit dimensions are listed in TABLE 1.

Electrical Properties of Dislocations in Plastically Deformed Float Zone Silicon

1995 ◽  
Vol 5 (9) ◽  
pp. 1327-1336 ◽  
Author(s):  
J. J. Simon ◽  
E. Yakimov ◽  
M. Pasquinelli
Keyword(s):  
Electrical Properties ◽  
Float Zone
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