DEFECT REDUCTION IN GAAS AND INP GROWN ON PLANAR SI(111) AND ON PATTERNED SI(001) SUBSTRATES

Low pressure metalorganic chemical vapour deposition (LP-MOCVD) of GaAs and InP on planar Si(111) and on patterned Si(001) with V-grooves on a sub-mu m scale is studied. For both, InP and GaAs grown on planar Si(111), the defect density is reduced by more than one order of magnitude as compared to layers grown on planar Si(001). In InP/Si(111) near the interface, an extended hexagonal misfit dislocation network with heavy twinning parallel to the interface is found, whereas in GaAs/Si(111) no twins are observed by high-resolution transmission electron microscopy. On sub-mu m V-grooved Si(001) a preferential nucleation on the Si{111}-facets is found both for InP and GaAs. InP and GaAs layers are completely planarized after less than 1 mu m thickness, in contrast to the growth of InP on mu m V-grooved Si(001). As-grown and InP layers of comparable thickness on sub-mu m V-grooved Si(001) exhibit values of the full widths at half maxima of the X-ray rocking curves which are between the two planar (001) and (111) cases. Scanning electron microscopy, transmission electron microscopy, double-crystal X-ray diffraction and spectroscopic ellipsometry yield consistent results.