Effect of in situ and ex situ annealing on dislocations in GaAs on Si substrates

Gallium arsenide layers grown by molecular beam epitaxy on (100) Si substrates were subjected to annealing under As overpressure at 650, 750, and 850 °C for 1/2 h. A substantial reduction in the dislocation density near the interface and in the bulk of the epitaxial layers was observed for the 850 °C anneal. In situ annealing at 700 °C for 1/2 h after 1/2 h of growth followed by a deposition of InGaAs/GaAs strained‐layer superlattices and bulk layers also resulted in reduced dislocation densities.