Misfit dislocations generated from inhomogeneous sources and their critical thicknesses in a InGaAs/GaAs heterostructure grown by molecular beam epitaxy

Misfit dislocations generated from inhomogeneous sources in InGaAs/GaAs strained-layer heterostructures grown by molecular beam epitaxy were investigated using transmission electron microscopy (TEM) with the lift-off technique. These inhomogeneous sources are suggested to be particulates. TEM investigations show that (1) the critical thicknesses of misfit dislocations generated from inhomogeneous sources are the same as those generated from preexisting threading dislocations, and (2) each inhomogeneous source may generate a number of misfit dislocations. These observations suggest that these inhomogeneous sources are a prime source of misfit dislocation generation.