METALORGANIC VAPOR-PHASE EPITAXIAL-GROWTH AND STRUCTURAL CHARACTERIZATION OF GAAS/INP HETEROSTRUCTURES

Highly mismatched GaAs epitaxial layers with thickness ranging from 15 nm to 7 mum have been grown on InP substrates by atomospheric pressure metalorganic vapor phase epitaxy. Layers thinner than 30 nm exhibited 3-D growth mechanism; in the thicker layers, the islands coalesced and then the growth followed the layer by layer mechanism. The elastic strain and the extended defects have been studied by high resolution x-ray diffraction and transmission electron microscopy, respectively. The common observation of planar defects, misfit, and threading dislocations in the layers has been confirmed. The results on the elastic strain release have been discussed on the basis of the equilibrium theory.