Study on thermal stress in a silicon ingot during a unidirectional solidification process

• Published in: Journal of crystal growth 2008-09, Vol.310 (19), p.4330-4335
• Main Authors: Chen, X.J., Nakano, S., Liu, L.J., Kakimoto, K.
• Format: Article
• Language: English
• Subjects: 02.60.Cb; 61.50.Ah; 81.10.−h; 81.40.Jj; A1. Computer simulation; A1. Heat transfer; A1. Solidification; A1. Stresses; Applied sciences; Cross-disciplinary physics: materials science; rheology; Electronics; Exact sciences and technology; Materials; Materials science; Methods of crystal growth; physics of crystal growth; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Physics; Solidification; Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2008.07.027

A transient global model was used to obtain the solution of a thermal field within the entire furnace during a unidirectional solidification process for photovoltaics. The melt–solid interface shape was obtained by a dynamic interface tracking method. The thermal stress distribution in the silicon ingot was solved using the displacement-based thermo-elastic stress model. Furthermore, several different melt–solid interface shapes were obtained by using different growth velocities, and then the thermal stresses for different solidification times were compared. The simulation results suggested that the crucible constraint should be reduced and a longer solidification time should be used for growing a silicon ingot with low thermal stress and low dislocation density.