DISLOCATIONS AND PRECIPITATES IN GALLIUM-ARSENIDE

A complete dislocation analysis on a large number of grown-in dislocations was performed on wafers taken from three different semi-insulating liquid encapsulation Czochralski GaAs single crystals. By determining the Burgers vector, line direction, and habit plane of nearly 800 dislocations a decision could be made on dislocation type, dislocation generation, and multiplication mechanisms. Taking into account possible dislocation reactions between stress-induced glide systems all detected glide systems could be explained. The influence of post-growth annealing on both dislocations and arsenic precipitates was also investigated. Little effect was found on dislocations. Arsenic precipitates, however, showed a different distribution in size and significant effects on fine structure giving information on their nucleation and growth mechanisms.