DISLOCATION GENERATION IN GAAS CRYSTALS GROWN BY THE BRIDGMAN METHOD USING A CRYSTALLOGRAPHIC MODEL

The objective of this paper is to predict the dislocation density in G aAs crystals grown from the melt using a crystallographic model. The e ffects of the temperature gradient field, the growth direction and the initial dislocation density on the dislocation multiplication in the crystal are investigated. The results show that a small increment in t emperature gradient results in a large increment in dislocation densit y. Comparison of the calculated dislocation density for the GaAs cryst al grown along the [001] and [111) directions shows that the growth di rection has a significant effect on dislocation multiplication. Disloc ation multiplication behaviour in the individual slip system is also i nvestigated. The dislocation density in the slip system is strongly af fected by the resolved shear stress in such a slip system, but only we akly affected by the initial dislocation density in the seed crystal.