Structural stability of low temperature grown InGaAs/GaAs heterostructure

Abstract

InGaAs/GaAs superlattice was grown by molecular beam epitaxy (MBE) on GaAs (100) substrate at low substrate temperature (250 degrees C). The as-grown superlattice sample was then annealed at various temperatures for 10 min. The as-grown superlattice was pseudomorphic and stable up to 800 degrees C annealing. Annealing at 850 degrees C or higher temperatures, however, caused strain relaxation accompanying with dislocation generation at the As precipitate. Dislocation generation at the As precipitate was influenced by two factors. The one is lattice mismatch between GaAs and As precipitate, and the other is elastic interaction force acting on the As precipitate.