STRUCTURAL-PROPERTIES OF GAAS/GE HETEROSTRUCTURES AS A FUNCTION OF GROWTH-CONDITIONS

The structural properties of atmospheric pressure, metal organic vapour phase epitaxy grown GaAs/Ge heterostructures were investigated by transmission electron microscopy and high-resolution X-ray diffraction as a function of substrate misorientation, V to III ratio, growth rate and temperature. A 3 degrees misorientation of the substrate is effective in suppressing the antiphase domains, but only in optimized growth th conditions. In the ranges considered, the strain release is influenced more by the misorientation angle and the V to III ratio than by the substrate temperature and the growth rate. The great majority of misfit dislocations are 60 degrees in character; occasionally they react to form edge segments. The misfit dislocations strongly interact with the antiphase boundaries. The contribution of the antiphase domains to strain relaxation is discussed.