Low threading dislocation density GaAs on Si(100) with InGaAs/GaAs strained-layer superlattice grown by migration-enhanced epitaxy

Abstract

This paper reports a promising approach for reducing the density of threading dislocations in GaAs on Si. In _x Ga_1-x As/GaAs strained-layer superlattices (SLSs) grown by migration-enhanced epitaxy at 300° C on GaAs/Si acted as barriers to threading dislocations. Unlike conventional high-temperature-grown SLSs, the low-temperature-grown SLSs were hardly relaxed by the formation of misfit dislocations at GaAs/SLS interfaces, and this allowed them to accumulate considerable strain. New threading dislocation generation due to the misfit dislocation was also suppressed. These factors caused effective bending of threading dislocations and significantly reduced the dislocation density. For the samples that had an SLS withx = 0.3, the average etch-pit density was 7 × 10⁴ cm^-2, which is comparable to that of GaAs substrates.