Effect of employing positions of thermal cyclic annealing and strained-layer superlattice on defect reduction in GaAs-on-Si

This paper describes the dependence of the dislocation density reduction effect on the employing position of either thermal cyclic annealing (TCA) or InGaAs-GaAs strained-layer superlattice (SLS) in GaAs-on-Si grown by metalorganic chemical vapor deposition (MOCVD). The dislocation density is reduced to one twenty-fifth of that in as-grown sample by the TCA as the position of TCA becomes farther than about 1.5 µm from the Si surface. The dislocation density is additionally reduced to one third by the SLS as the position of SLS becomes farther than about 2.0 µm. As a result, the dislocation density is reduced to 1.5 × 10 6 cm -2 by the combined use of TCA and SLS. The dislocation density reduction effect of TCA is determined mainly by the degree of residual stress. That effect of SLS is determined mainly by the degree of additional stress generated by SLS.