Comparative analysis of thermal stress induced dislocations in 7 kg, 40 kg and 330 kg multi-crystalline silicon ingots grown by directional solidification

In this paper, transient heat and mass transfer numerical simulations have been done to analyse the variation in thermal stress induced dislocations in 7 kg, 40 kg and 330 kg mc-silicon ingots grown using Directional Solidification (DS) furnace. The thermal parameters such as temperature distribution, principal stress, shear stress and von Mises stress distribution are examined. The effect of ingot size on temperature parameters, solid/melt interface, stress distribution and dislocation generation are investigated to obtain essential information needed for system design. It is observed that with respect to increase in size of the ingot the convexity of solid/melt interface decreases and the uniformity in radial and axial distribution of temperature and thermal stress also increase thereby decreasing the dislocation generation in the grown mc-silicon ingot. It shows that furnace design and ingot size play a crucial role in generation of thermal stress induced dislocation and defects in the grown ingot.