Effect of cooling rate on the activation of slip systems in seed cast-grown monocrystalline silicon in the [001] and [111] directions

To effectively reduce dislocation by controlling the cooling process, the effect of cooling rate on the activation of slip systems was studied in seed cast-grown monocrystalline silicon in the [001] and [111] growth directions. The results show that the cooling rate has a large effect on the activation of slip systems. In the [001] growth direction, a slow cooling rate either weakly activates 4-fold symmetric slip systems or does not activate them at all. In contrast, a fast cooling rate strongly activates the 4-fold symmetric slip systems. In the [111] growth direction, a slow cooling rate weakly activates the three 3-fold symmetric slip systems, while a fast cooling rate strongly activates the three 3-fold symmetric slip systems. The differences of the activation of the slip systems between the slow and fast cooling rates mainly cause differences in dislocation and residual stress. Irrespective of the crystal growth direction, it is mainly the radial flux that causes the difference between the fast and slow cooling rates. Therefore, the most effective method for reducing dislocation during the cooling process is to decrease the radial flux.