Experimental study on the interaction between Al and P in Si solution

The effect of impurity interactions on impurity removal efficiency in metallurgical grade silicon (MG-Si) was studied and analyzed to provide a new idea for removing impurities from MG-Si. This paper provides theoretical support for the removal of nonmetallic impurity P during the metallurgical purification and preparation of crystalline silicon. The interaction between Al and P in liquid silicon were investigated by directional solidification. The effects of different pull-down speeds, refining temperatures, holding times and Al contents on the distributions Al and P were investigated. The experimental results of the directional solidification of the Si-P-Al ternary system showed that from the bottom to the top of the sample, the contents of Al and P gradually increased. This phenomenon verifies the accuracy of the activity interaction coefficient between Al and P in the Si-P-Al ternary system calculated by the model. The mutual attraction between Al and P was also confirmed.