Study of dislocation density in Te-doped GaSb single crystals grown by means of Czochralski technique

A series of Te-doped GaSb single crystals were grown by means of the Czochralski method without encapsulant in a hydrogen atmosphere. The possible influence of tellurium in decreasing the dislocation density was studied, but no such effect was observed because the temperature gradients in the furnace were very low, thus considerably lowering the possibility of stress creation on the solidification surface. However, it was found that the elimination of dislocations at the beginning of the growth procedure of GaSb grown in the 〈111〉 direction was influenced by the angle which the shoulders of the crystal included. The critical angle was determined as 38.94°. Below this value the dislocations were grown out and the dislocation density rapidly decreased in the course of crystal growth.