US Patent 7427327 Silica glass crucible with barium-doped inner wall

A silica glass crucible includes a thin barium-doped inner layer, a stable, bubble-free intermediate layer, and a stable opaque outer layer. The fusion process of the present invention controls the dynamic gas balance at the fusion front where formed grain is melted to dense fused silica. The crucible demonstrates reduced bubble growth during a Czochralski process. As a result of the thin barium-doped layer and the reduced bubble growth, the inner surface of the crucible is uniformly minimally textured during a CZ process. The present crucible is especially suited for intense CZ processes for manufacturing silicon ingots used for solar cells or with silicon that is heavily doped with antimony, boron, or arsenic.