Numerical Modeling of Stress and Dislocations in Si Ingots Grown by Seed-Directional Solidification and Comparison to Experimental Data

Unsteady modeling of the thermal stress and dislocations in silicon ingots grown by seed-directional solidification has been done for three cooling regimes to study the effect of the model parameters. To track the history of dislocation multiplication, our computations continuously consider the growth process from the beginning of crystallization on the seed to the end of cooling of the grown crystal. The way that a cooling regime may affect the residual stress and dislocation distribution in the crystal is discussed. The computational results show good agreement with experimental data for both residual stress and dislocation density. Our results have confirmed that conjugated unsteady modeling is a promising way to investigate the effect of various growth conditions as well as the growth system design on the residual stress distribution, which is an important parameter of crystal quality.