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 GaA s 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 S i(111), the defect density is reduced by more than one order of magnit ude 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 mi croscopy. On sub-mu m V-grooved Si(001) a preferential nucleation on t he 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 contras t to the growth of InP on mu m V-grooved Si(001). As-grown and InP lay ers of comparable thickness on sub-mu m V-grooved Si(001) exhibit valu es 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 m icroscopy, transmission electron microscopy, double-crystal X-ray diff raction and spectroscopic ellipsometry yield consistent results.