A STUDY OF CONVECTION, STRIATIONS AND INTERFACE SHAPE IN INP CRYSTALSGROWN BY THE DOUBLE-CRUCIBLE LEC TECHNIQUE

A double-crucible (DC) Czochralski setup has been used for tl-le pulli ng of semi-insulating Fe-doped InP. The level of the Fe-doped melt in the growth crucible is replanished with the undoped InP from the reser voir crucible. In this way, since the distribution coefficient of iron is very small (about 0.001), the Fe concentration in the growth cruci ble is virtually unchanged during the pulling so that the axial Fe con centration is much more uniform than in standard LEC crystals. The use of two concentric crucibles has great implications in terms of convec tive flows, stability of the melt temperature and interface shape. In this paper we report the results of a study on striations and structur al defects in InP grown from a double-crucible LEC arrangement. A dime nsionless relationship for correlating striation features with melt mo tions is also proposed.