BETHGE AND FRANK STEP SOURCES IN SOLUTION GROWTH OF GAAS

Using transmission electron microscopy, we analyse dislocations that g enerated growth pyramids on (001) facets of solution grown GaAs. In sa mples prepared at high temperatures all active dislocations represent Frank step sources, i.e. are dislocations that have a Burgers vector c omponent perpendicular to the growth surface. In samples grown at low temperatures, 10 to 20% of the active sources are Bethge step sources, i.e. dislocations whose Burgers vector is contained within the growth surface. A model case describes how the microscopic growth process in teracts with the dissociated dislocation at the growth interface. This model helps to explain our earlier published observations made on GaA s and Si.