FORMATION OF INTERFACIAL PHASES BETWEEN SILICA AND UNDOPED OR ANTIMONY-DOPED SILICON MELTS

Interfacial phase formation during dissolution of silica in undoped or Sb-doped Si melts were studied using electron probe microanalysis. Results showed that reaction between silica and the Si melt depended on the Sb concentration in the Si melt. A foil-shaped interfacial phase with a composition about SiO1.8 appeared between the Si melt and the wall of the silica ampoule when the Sb concentration was less than 0.5 at. %. However, the interfacial phase changed both in shape and composition when the Sb concentration was higher. The shape of the interfacial phase became dendritic and the composition was SiO2 when the Sb concentration was in the range from 0.5 to 2.0 at. %. The interfacial phase disappeared when the Sb concentration was higher than 2.0 at. %.