Low Threading Dislocation Density GaAs on Si(100) with InGaAs/GaAs Strained-Layer Superlattice Grown by Migration-Enhanced Epitaxy

This paper reports on a new approach for reducing the threading dislocation density in GaAs on Si. We have used In x Ga 1- x As/GaAs strained-layer superlattices (SLSs) grown on GaAs/Si at 300°C by migration-enhanced epitaxy as threading dislocation barriers. Different from conventional high-temperature-grown SLSs, the low-temperature-grown SLSs are only slightly relaxed by misfit dislocation formation at GaAs/SLS interfaces. Thus, considerable strain can be accumulated in SLS. In addition, new threading dislocation generation due to the misfit dislocation can be suppressed. These factors lead to effective threading dislocation bending and to significant reduction in the dislocation density. For the samples with a SLS of x =0.3, the average etch-pit density is 7×10 4 cm -2 , which is the lowest value ever reported.