Investigation of X-ray satellite reflections attributed to antiphase boundaries in epitaxial (Ga,In)P layers grown on (001) GaAs substrates

We report on the analysis of additional X-ray reflections that probably ari se from antiphase domain boundaries within (Ga,In)P/(001) GaAs heteroepitax ial layers. Due to the preferred cation ordering along the crystallographic directions [1 (1) over bar 1] and [1 (1) over bar 1] which belong to the [ 110] zone the original sphalerite-type structure of (Ga,In)P changes into a CuPt-like of the cation sublattice. This ordering phenomenon causes a loss of symmetry, i.e. the cubic structure is converted into a rhombohedral one . The antiphase boundaries between ordered domains are assumed to behave si milar to lattice planes at X-ray diffraction. Therefore, additional reflect ions may occur spatially neighboured to the [001] direction. The presented results of X-ray experiments are discussed in relation to TEM experiments p ublished in the literature in order to explain the origin of the satellite reflections. In the case of the investigated samples (grown on GaAs substra tes misoriented 2 degrees towards the azimuthal [010] direction) the APBs r un preferentially in directions tilted up to angles of 20 degrees with resp ect to growth direction. A preferential occurrence of satellite reflections in <13 2 1> directions was observed coinciding with {13 2 1} "lattice plan es" whose normals enclose the same angle to the [001] growth direction as t he normals of the average planes characterized by APBs. The appearence of t he phenomenon in other directions that are also spatially neighboured to th e <13 2 1> directions was determined on the basis of the shift of the refle ction positions due to tilting the sample around an axis geometrically incl uded in the scattering plane.