Analysis of strained-layer superlattice effects on dislocation density reduction in GaAs on Si substrates

High quality GaAs films with dislocation densities of 1–2×106 cm−2 on (100)Si substrates have been obtained for combination of strained-layer superlattice insertion and thermal cycle growth using the metalorganic chemical vapor deposition method. In this letter, remarkable reduction effects of dislocation density in the GaAs layers due to InGaAs/GaAs and InGaAs/GaAsP strained-layer superlattice insertion on Si have been analyzed by calculating the dislocation force exerted by the misfit due to the strained-layer superlattice insertions. Threshold layer thickness needed for dislocation reduction and critical thickness for dislocation generation have been clarified for several strained-layer superlattice systems.