Epitaxial GaAs/Ca0.5Sr0.5F2(1800 Å)/GaAs heterostructures have been grown by molecular‐beam epitaxy on (100), (111)A, (511)A, (511)B, (711)A, and (711)B GaAs substrates. We used reflective high‐energy electron diffraction, Auger electron spectroscopy, low‐energy electron diffraction, Rutherford backscattering (RBS), scanning electron microscopy, and Raman scattering to study the surface morphology, crystallinity, and chemical composition of these films. On the (100) orientation, the top GaAs had a flat microstructure; the surface crystallinity improved with increased thickness from 500 Å to 1 μm, but the size of grains due to antiphase disorder also increased with thickness. On the (111)A orientation, the GaAs formed (100)‐facets to lower the surface free energy. The surface morphology and near‐surface crystallinity improved with increased thickness. The top GaAs films from (511)A and (511)B substrates showed the best near‐surface crystallinities from RBS, electron channeling pattern, and Raman scattering experiments. The properties of top GaAs on (711)A and (711)B substrates were not as good as those from (511)s, but better than those from (100) and (111)A.