Reduction of Dislocation Density in GaAs/Si by Strained-Layer Superlattice of InxGa1-xAs-GaAsyP1-y

Dislocation density in GaAs layers grown on Si substrates has been investigated by measuring in-depth profile of the etch pit density (EPD) using a molten KOH. Reduction of EPD into 10 7 cm -2 level for the layer of 2-3 µm thickness is attained by the post annealing at 900°C for 30 min. Further reduction of dislocation has been achieved using In x Ga 1- x As-GaAs y P 1- y strained-layer superlattices (SLS's); step-like reduction of the dislocation at the SLS's and its continuous decrease even passing through the SLS's have been observed.