Magnetic field effects on float-zone Si crystal growth

Robertson, Glenn D.; O'Connor, Dennis J.

doi:10.1016/0022-0248(86)90015-1

Cited by 53 publications

(15 citation statements)

References 10 publications

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“…It was determined that the application of a magnetic field during directional solidification of materials can significantly reduce the thermosolutal buoyant flow. [3][4][5] Nevertheless, the effect of a steady-state magnetic field applied during the solidification of the metallic alloy is not always well understood. During directional solidification in the dendritic regime, some unexpected behaviors were observed.…”

Section: Introductionmentioning

confidence: 99%

Effects of Thermoelectric Magnetic Convection on the Solidification Structure During Directional Solidification under Lower Transverse Magnetic Field

Ren

Gagnoud

et al. 2011

Metall Mater Trans A

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This work investigated the thermoelectric magnetic convection (TEMC) during directional solidification under a transverse magnetic field numerically and experimentally. Numerical results show that the TEMC will form in liquid near the liquid/solid interface and in the dendritic network. The value of the TEMC mainly depends on the crucible diameter, the temperature gradient, and the magnetic field intensity. The value of the TEMC increases as the crucible diameter and the temperature gradient are increased. The value of the TEMC on the sample scale increases to a maximum when the magnetic field is of the order of 0.1 T, and then decreases as the magnetic field still increases. However, the value of the TEMC on the cell/ dendrite scale continues to increase with the increase of the magnetic field intensity when the applied magnetic field is less then 1 T. Two alloys are solidified directionally in the vertical configuration under a transverse magnetic field, and results show that the application of a lower transverse magnetic field (B < 1 T) modified the liquid/solid interface shape and the cellular/ dendritic array significantly. Indeed, it was observed that, along with the refinement of the cell/ dendrite, the magnetic field caused the deformation of the liquid/solid interfaces and the extensive segregations (i.e., channel and freckle) in the mushy zone. Comparison of the numerical and experimental results shows that the modification amplitude of the liquid/solid interface and the cellular/dendritic morphology is in good agreement with the value of the TEMC at the liquid/solid interface and in the dendritic network. This implies that changes of the interface shape and the cellular/dendritic morphology should be attributed, respectively, to the TEMC on the sample and the cell/dendrite scales.

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Section: Introductionmentioning

confidence: 99%

Effects of Thermoelectric Magnetic Convection on the Solidification Structure During Directional Solidification under Lower Transverse Magnetic Field

Ren

Gagnoud

et al. 2011

Metall Mater Trans A

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“…There is no doubt that both axial uniform magnetic field and transversal uniform magnetic field could suppress convection in crystal growth and alleviate the oscillation of convection; however, related work indicates that radial segregation occurs under axial uniform magnetic fields [1][2][3][4], which is unfavorable to the growth of high-quality crystal; the axisymmetry of crystal growing environment is broken by transversal uniform magnetic fields, causing asymmetrical growing interface [5,6]. Accordingly, it is of great value to study how to optimize convection control by nonuniform static magnetic field generated by coils.…”

Section: Introductionmentioning

confidence: 97%

Influence of transverse magnetic field on thermocapillary flow in liquid bridge

Zeng

Yao

et al. 2011

Cryst. Res. Technol.

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For exploring the optimizing convection control technique by external magnetic field in floating zone crystal growth of semiconductor under microgravity, thermocapillary flow in a floating half-zone model is simulated numerically, and the influences of both the transversal uniform magnetic field and the magnetic field generated by transversal four coils on thermocapillary flow are investigated. The results indicate that the transversal uniform magnetic field is likely to break the axisymmetrical structure of thermocapillary flow, which is unfavorable to the growth of high-quality crystal; under the magnetic field generated by transversal four coils, both the mean and the maximum velocities increase with the increment of the distance between coils or the decrement of coil radius; and the convection tends to be more axisymmetrical with increasing coil radius. Compared to the transversal uniform magnetic field, the magnetic field generated by transversal four coils of appropriate radius and relative distance may not only suppress convection, but also enhance the axisymmetry of convection at the same time, and finally, the better convection control can be achieved.

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“…Most of the early works aim to reduce or alter the steady state, in other words, to decrease the effective Marangoni number, and thus to attenuate the fluctuation. For example, a well-known method is to apply a magnetic field to an electronically conductive melt [5][6][7][8]. Others are counteracting the surface flow by generating a stream by end-wall vibration [9][10][11][12] or directing a gas jet parallel to the surface [13].…”

Section: Introductionmentioning

confidence: 99%