2000 Volume 40 Issue Suppl Pages S148-S152
Dependence of the surface tension of molten silicon on temperature, the oxygen partial pressure in ambient argon atmosphere have been determined at temperatures ranging from 1693 to 1873K and in the range of PO2 from 10-25 to 10-14 MPa using a high purity BN substrate with the sessile drop method. Change of the surface tension with the oxygen partial pressure is very small in the range of PO2≤10-22 MPa. The surface tension decreases remarkably with increasing the oxygen partial pressure in the range of PO2 from 10-22 to 10-20 MPa, and increases slightly with increasing the oxygen partial pressure in the range of PO2>PO2, sat. The temperature coefficient of surface tension, δσ/δT, is minus and increases with increasing PO2, δσ/δT at PO2=10-25 MPa is equal to about -0.74 mN·m-1·K-1 and then δσ/δT gradually increase with increasing the oxygen partial pressure up to 10-22 MPa. δσ/δT steeply increases with increasing the oxygen partial pressure in the range of PO2 from 10-22 to 10-20 MPa. And again gradually increases with further increases of PO2 up to 10-15 MPa, where δσ/δT is equal to -0.15 mN·m-1·K-1. It is found that the surface tension of molten silicon and its temperature coefficient are sensitive to the oxygen partial pressure of argon atmosphere in the measuring system.
