Directional solidification of silicon under the influence of travelling magnetic field

Cablea, M.; Zaïdat, K.; Gagnoud, A.; Nouri, A.; Delannoy, Yves

doi:10.1016/j.jcrysgro.2013.11.062

Cited by 23 publications

(11 citation statements)

References 9 publications

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“…Heat conservation equation (1) Heat conservation at the interface (2) Temperature continuity at the interface (3) Impurity concentration equation (4) Impurity conservation at the interface (5) Phase diagram relation (6) In these equations, is the thermal conductivity, is the thermal capacity, is the density, is the latent heat of fusion, and is the solutal diffusivity.…”

Section: Meyer's Original Methodsmentioning

confidence: 99%

“…The continuous development of computational resources and the need for a better understanding of the phenomena and for optimization of industrial processes have led to the development of several numerical modelling strategies in the last decades. Numerous efforts have been made to develop realistic 2D and 3D simulation tools using either an enthalpy approach featuring a diffuse interface computed on a fixed mesh [1][2][3][4][5] or resorting to adaptive meshing techniques to track the solidification front and insure its fine description with nodes located on the interface [6][7][8][9][10][11]. Combining coupled 2D and 3D simulations is now an established strategy to reduce computational cost in particular in the Czochralski configuration in which the front is nearly fixed in space [12,13].…”

Section: Introductionmentioning

confidence: 99%

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An efficient 1D numerical model adapted to the study of transient convecto-diffusive heat and mass transfer in directional solidification

Tavernier

Millet

Henry

et al. 2017

International Journal of Heat and Mass Transfer

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International audienceWe combine an effective diffusivity model with a numerical approach initially proposed by Meyer (1981) to simulate transient heat and mass transfer phenomena in a directionally solidifying Sn-Bi rod. This particularly efficient 1D numerical model is light enough to be used within the frame of optimization methods at reasonable numerical cost. This approach is tested against reference in situ measurements obtained under microgravity conditions during the Mephisto program. We simulate the final homogenization transient of several experimental runs with different pulling velocities. The solid/liquid interface temperature evolution with time is extracted from the simulations and compared with that obtained by Seebeck in line measurements. After optimization of the model the observed discrepancy between the simulated and measured data is less than 1.5%. This validates both the proposed very efficient 1D numerical approach and the consistency of the set of thermophysical parameters values for dilute Sn-Bi alloys

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Section: Meyer's Original Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An efficient 1D numerical model adapted to the study of transient convecto-diffusive heat and mass transfer in directional solidification

Tavernier

Millet

Henry

et al. 2017

International Journal of Heat and Mass Transfer

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“…The application of TMF during solidification of the Al-Si-Sn melt induces a recirculating flow in the radialmeridional plane, which consists of a double-vortex structure. Hence, a strong outward flow from the axis of the ingot towards the solidification front occurs where symmetrical segregation channels emerge [14,[18][19][20] . Such periodical flow structure, carrying the bulk liquid with higher Si content, promotes the growth of the primary Si formed close to the inner wall of the crucible where the temperature is lower.…”

Section: (B)-(d)mentioning

confidence: 99%

Separation of primary Si and impurity boron removal from Al-30%Si-10%Sn melt under a traveling magnetic field

et al. 2016

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C rystalline silicon is one of the materials used for solar cells, accounting for over 90% of the photovoltaic (PV) materials [1] . However, the PV industry has to face a serious low-cost feedstock supply shortage due to a rapid expansion of the solar cell industry. To lower the production cost of Si solar cells, a promising way is to upgrade metallurgical-grade silicon (MGSi) to solar-grade silicon (SoG-Si) with metallurgical treatments [2][3][4][5] . However, boron (B) element, an impurity in MG-Si, cannot be removed efficiently because of its low vapor pressure (lower than that of Si) [6] and large segregation coefficient (0.8 at 1,414 ºC) [7] . In recent years, considerable progress has been made in B removal from the MG-Si using hypereutectic Al-Si alloy solidification refining process at low temperatures [8][9][10][11] . In the alloy solidification process, the primary Si initially precipitates from supersaturated melt with decreasing Abstract: Separation of primary Si phase and removal of boron in the primary Si phase during the solidification process of the Al-30%Si-10%Sn melt under a traveling magnetic field (TMF) were investigated. The results showed that the agglomeration layer of the primary Si can be formed in the periphery of the ingot while the inner microstructures mainly consist of the eutectic α-Al+Si and β-Sn phases. The intense melt flow carries the bulk liquid with higher Si content to promote the growth of the primary Si phase which is first precipitated close to the inner wall of crucible with a relatively lower temperature, resulting in the remarkable segregation of the primary Si phase. The content of impurity B in the primary Si phase can be removed effectively with an increase in magnetic flux intensity. The results of electron probe microanalysis (EPMA) clearly indicated that the average intensity of the B Ka line in the α-Al phase region of Al-Si-Sn alloy is higher in the case of solidification under TMF than that of normal solidification condition, suggesting that the electromagnetic stirring can promote the B removal from the primary Si phase. temperature, during which more impurities, especially B, are enriched in the alloy by redistributing the impurities to the solid/liquid (S/L) interface. Adding pure Sn to the hypereutectic Al-Si alloy can effectively expand the crystallization temperature range to promote the growth of the primary Si [12,13] . However, considering the diffusion kinetics of the impurities at the nearby growing Si surface, a more effective enhanced S/L segregation tendency of impurities has not been achieved.In the present study, the traveling magnetic field (TMF) was applied during solidification of the Al-30%Si-10%Sn melt to separate the primary Si. Furthermore, the effect of the electromagnetic stirring on B removal from the primary Si during the solidification of the Al-30Si-10Sn melt was investigated. Experimental procedureCommercial purity Al (99.7 wt.%), Sn (99.99 wt.%) and MG-Si (99.7 wt.%) (all the compositions quoted in this work are in wt.% unless ot...

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“…Recently, lots of studies have indicated that optimizing the solidification process can reduce the impurity in polysilicon [5][6][7][8][9][10][11][12]. Factors like growth rate [10], the power ratio of heaters [13,14] and the magnetic field [15][16][17][18] affect the content of impurities in the silicon significantly.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Effect of a Vertical Magnetic Field on Melt Convection and Oxygen Transport During Directional Solidification of Multi-Crystalline Silicon by Numerical Simulation

et al. 2019

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Melt convection during the directional solidification process of multi-crystalline silicon plays a critical role in the transport of impurities. The utilization of a static magnetic field is an effective way to control the melt convection pattern. Studying the effect of the Lorentz force induced by the vertical magnetic field (VMF) on the melt convection of silicon in detail is beneficial to optimize the magnetic field parameters in the production process. Based on the numerical simulation method of multi-physics coupling, this paper explores the effects of different VMF intensities on the convection of silicon melt and the transport of oxygen in the melt during the directional solidification of polycrystalline silicon. The results show that in the first 125 minutes of the crystallization stage, the melt convection velocity is affected significantly by the magnetic field intensities. When different convection circulations are present in the silicon melt, the upper circulation easily transports oxygen to the furnace atmosphere, and the subjacent circulation easily lead to the retention and accumulation of oxygen. Enhancing the VMF intensity to a certain extent can reduce the size of the oxygen retention region in the silicon melt, and the time of the first disappearance of the subjacent circulation near the sidewall of the crucible is shortened. Then the average oxygen concentration in the silicon melt can be reduced. However, a larger vertical magnetic field intensity can result in greater average oxygen concentration in the oxygen retention region.

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Directional solidification of silicon under the influence of travelling magnetic field

Cited by 23 publications

References 9 publications

An efficient 1D numerical model adapted to the study of transient convecto-diffusive heat and mass transfer in directional solidification

An efficient 1D numerical model adapted to the study of transient convecto-diffusive heat and mass transfer in directional solidification

Separation of primary Si and impurity boron removal from Al-30%Si-10%Sn melt under a traveling magnetic field

Analysis of the Effect of a Vertical Magnetic Field on Melt Convection and Oxygen Transport During Directional Solidification of Multi-Crystalline Silicon by Numerical Simulation

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