Influence of Fe on the Distribution Characteristics of P in Silicon Melt During Directional Solidification

Other impurity components in silicon melt at high temperature will affect P removal from metallurgical-grade silicon (MG–Si). Fe is one of the most abundant impurities in silicon and therefore probably affects P removal. In this paper, the effect of Fe on characteristics of P distribution in silicon melt during directional solidification experiments was investigated based on activity interaction coefficients of Fe to P in Si–P–Fe melt. The experimental results show that overall trend of P enrichment in experimental samples of MG–Si and Si–P alloys, but the difference in P content of each part is not significant. In the experimental samples of Si–P–Fe alloys, contents of Fe and P show a gradual increase from bottom to the top of samples. The enrichment area of P is highly overlapped with that of Fe, and P and Fe are always distributed together, confirming that Fe carries part of P along with segregation to top of sample during directional solidification process. The electron probe microanalysis results show that P forms a high enrichment within Fe distribution area in top position of sample. It is further shown that co-segregation of Fe and P occurs under the interaction force between Fe and P during directional solidification process.