Compositional analysis and evolution of defects formed on GaInP epilayers grown on Germanium

In this work, a compositional and morphological study of GaInP layers grown on Ge substrates is presented. The samples have been evaluated by means of high resolution X-ray diffraction, Rutherford backscattering channeling, atomic force microscopy and scanning electron microscopy. Compositional results from HRXRD and RBS show that the quality of samples close to the lattice match are independent on the composition (Ga or In-rich), although for Ga-rich samples, the spectra from RBS channeling measurements is not equal for one 〈110〉〈110〉 direction and its perpendicular, an effect that does not appear in In-rich samples. Concerning, the morphological results, two typical defects appear on GaInP nucleation layer on Ge substrate–the so called arrowhead defects and asymmetric truncated pyramids–both orientated along 〈110〉〈110〉 directions. Experiments reveal that the formation of pyramids is independent on the layer composition, while the density of arrowheads increases as the layer gets more Ga-rich.