Reaction at the interface between Si melt and a Ba-doped silica crucible

A silica crucible with Ba doping at inner surface was used for growing a Czochralski Si (CZ-Si) crystal. Reaction at the interface between Si melt and a Ba-doped silica crucible was investigated. It was found that generation of brownish rings could be suppressed effectively by Ba doping with proper concentration. Almost no brownish rings formed at a silica crucible after Si crystal growth when Ba concentration was more than 100 ppm. Instead of the brownish rings, a white uniform cristobalite layer formed at the inner surface of the Ba-doped silica crucible. The surface of the cristobalite layer was very smooth and no traces of release of flakes or particles could be identified from the surface even after the Si crystal growth.