Search results for "Crucible"

Particle transport in recirculated liquid metal flows

2008

PurposeAims to present recent activities in numerical modeling of turbulent transport processes in induction crucible furnace.Design/methodology/approach3D large eddy simulation (LES) method was applied for fluid flow modeling in a cylindrical container and transport of 30,000 particles was investigated with Lagrangian approach.FindingsParticle accumulation near the side crucible boundary is determined mainly by the ρp/ρ ratio and according to the presented results. Particle settling velocity is of the same order as characteristic melt flow velocity. Particle concentration homogenization time depends on the internal flow regime. Separate particle tracks introduce very intensive mass exchang…

Numerical analysis of the influence of ultrasonic vibration on crystallization processes

2011

The challenge in the future fabrication of semiconductor bulk crystals is the improvement of the crystal quality with a simultaneous increase of the yield. For that, a proper control of mass transfer within the fluid phase is required. Besides the damping of violent convective fluctuations, the thickness of the diffusion boundary layer, causing morphological instability, has to be decreased. The influence of ultrasound in molten Germanium was analyzed by numerical simulations. The simulations were provided by applying commercial software packages ANSYS ® and FLUENT ® . ANSYS ® was used to model the ultrasonic wave propagation in the whole growth system consisting of melt and crystal, crucib…

LES modelling of recirculated flows in crucible furnaces

2006

Improving the material quality of silicon ingots by aluminum gettering during crystal growth

2016

We present a method for the purification of silicon ingots during the crystallization process that reduces significantly the width of the low charge carrier lifetime region at the ingot top. The back-diffusion of impurities from the ingot top is suppressed by adding a small amount of pure aluminum into the silicon melt right at the end of the solidification. We study the aluminum gettering effect by instrumental neutron activation analysis (INAA) and Fei imaging. Furthermore, we present a model for aluminum gettering of Fe in the silicon ingot that is in agreement with literature data for aluminum gettering at lower temperature. The distribution of iron in the ingots with and without alumin…

Charge transport properties in CdZnTe detectors grown by the vertical Bridgman technique

2011

Presently, a great amount of effort is being devoted to the development of CdTe and CdZnTe (CZT) detectors for a large variety of applications such as medical, industrial, and space research. We present the spectroscopic properties of some CZT crystals grown by the standard vertical Bridgman method and by the boron oxide encapsulated vertical Bridgman method, which has been recently implemented at IMEM-CNR (Parma, Italy). In this technique, the crystal is grown in an open quartz crucible fully encapsulated by a thin layer of liquid boron oxide. This method prevents contact between the crystal and the crucible, thereby allowing larger single grains with a lower dislocation density to be obta…

Charge Transport Properties in CZT Detectors Grown by the Vertical Bridgman Technique

2010

Great efforts are being presently devoted to the development of CdTe and CdZnTe detectors for a large variety of applications, such as medical, industrial, and space research. We present the spectroscopic properties of some CZT crystals grown by the standard vertical Bridgman method and by the boron oxide encapsulated vertical Bridgman method, which has been recently implemented at IMEM-CNR (Parma, Italy). By this technique the crystal is grown in an open quartz crucible fully encapsulated by a thin layer of liquid boron oxide. This method prevents contact between the crystal and the crucible thereby allowing larger single grains with a lower dislocation density to be obtained. Several mono…

Applicability of LES turbulence modeling for CZ silicon crystal growth systems with traveling magnetic field

2010

Abstract To examine the applicability of LES turbulence modeling for CZ silicon crystal growth systems with traveling magnetic fields, LES calculations with Smagorinsky–Lilly turbulence model and van Driest damping at the solid walls are carried out. The program package for the calculations was developed on the basis of the open-source code library OpenFOAM ® . A previously published laboratory model with low temperature melt InGaSn, a 20” crucible, and process parameters corresponding to industrial Czochralski silicon systems is considered. Flow regimes with two crystal and crucible rotation rates and with different strengths of the traveling magnetic field “down” are analyzed. The calcula…

Fontaines (Saône-et-Loire). Place de l’Église [notice archéologique]

2019

Le village actuel de Fontaines, situé à environ 8 km au N.-O. de Chalon-sur-Saône, se développe sur 1,5 km de long selon un unique axe E-O, depuis la montagne Saint-Hilaire à l’ouest, occupée au Néolithique puis durant l’Antiquité tardive et le haut Moyen Âge, jusqu’à l’église paroissiale Saint-Just, à l’est. Malgré une emprise limitée et contrainte par de nombreux réseaux existants, l’opération a permis de documenter l’environnement immédiat de l’église, occupé depuis l’Antiquité jusqu’à nos jours.