Study of surface microstructure origin and evolution for GaAs grown on Ge/Si_1-xGe_x/Si substrate

The origin and evolution of surface microstructures in the GaAs layer grown on the Ge/Si_1-xGe_x/Si substrate were studied. The characteristic surface microstructures are formed in pairs. By correlating the results from atomic force microscopy and cross-sectional transmission electron microscopy characterization, these paired surface microstructures are identified as {1 1 1} stacking faults that propagate at 54° with respect to the substrate surface. The stacking faults originate from the single-stepped GaAs/Ge heterointerface, as a consequence of in situ annealing of the Ge surface. The surface microstructure density becomes lower and the mean lateral size larger when the GaAs thickness is increased from 0.54 to 1.11 νm.