X-ray diffraction characterization of Low Temperature grown GaAs/InP epilayers

In the present work low temperature GaAs epitaxial layers grown by molecular beam epitaxy on InP semi-insulating substrates and annealed at different temperatures have been extensively characterised by high resolution X-ray diffraction and X-ray topography to determine the crystal quality and the residual strain of the highly mismatched GaAs epilayer. The results of the X-ray characterization indicate that in all the samples a negligible residual strain is detected except in a thin region near the GaAs/InP interface and that the GaAs lattice parameter and the full width at half maximum (FWHM) of the GaAs 004 peak decrease when increasing the annealing temperature from 360 to 640 degC, indicating an improvement of the epilayer quality