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International Journal of Photoenergy
Volume 2013 (2013), Article ID 670315, 7 pages
http://dx.doi.org/10.1155/2013/670315
Research Article

Preservation of Seed Crystals in Feedstock Melting for Cast Quasi-Single Crystalline Silicon Ingots

1Key Laboratory of Thermo-Fluid Science and Engineering, Ministry of Education, School of Energy and Power Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi 710049, China
2State Key Laboratory for Mechanical Behavior of Materials, School of Materials Science and Engineering, Xi’an Jiaotong University, Xi’an 710049, China
3Yingli Green Energy Holding Co., Ltd., Baoding, Hebei 071051, China

Received 29 May 2013; Accepted 12 September 2013

Academic Editor: Chun-Sheng Jiang

Copyright © 2013 Zaoyang Li et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The preservation of seed crystals is important for the casting of quasi-single crystalline (QSC) silicon ingots. We carried out transient global simulations of the feedstock melting process in an industrial-sized directional solidification (DS) furnace to investigate key factors influencing seed preservation. The power distribution between the top and side heaters is adjusted in the conventional furnace for multicrystalline silicon ingots and in the evolved furnace with a partition block for QSC silicon ingots. The evolution of the solid-liquid interface for melting and the temperature distribution in the furnace core area are analyzed. The power distribution can influence the temperature gradient in the silicon domain significantly. However, its effect on seed preservation is limited in both furnaces. Seed crystals can be preserved in the evolved furnace, as the partition block reduces the radiant heat flux from the insulation walls to the heat exchange block and prevents the heat flowing upwards under the crucible. Therefore, the key to seed preservation is to control radiant heat transfer in the DS furnace and guarantee downward heat flux under the crucible.