RELATIONSHIP BETWEEN DIFFERENT INTERFACIAL PHASES AND OXYGEN SOLUBILITY IN SILICON MELT

Different interfacial phases formed at the interface between undoped or Sb-doped Si melt and SiO2 were observed, and the relationship between the interfacial phases and oxygen solubility in the Si melts was investigated. A foil-form interfacial phase with composition of about SiO1.8 appeared between the bulk Si melt and SiO2 ampule wall when the Sb concentration in the Si melt was less than 0.5 at%. However, the from of the interfacial phase became dendritic and composition changed to SiO2 when the Sb concentration was in the range from 0.5 to 2.0 at%. The interfacial phase disappeared when the Sb concentration reached about 2.0 at%. Corresponding to the different interfacial phases, the equilibrium oxygen concentrations in the Si melt also changed considerably, i.e., from 2 x 10(18) at/cm3 to about 2 x 10(19) at/cm3.