Interpretation of scanning high-energy electron diffraction measurements with application to GaAs surfaces

SHEED measurements have been made on the surface of GaAs crystals during in situ epitaxial deposition. The (bulk) spot pattern changes to a streak pattern as deposition proceeds, as noted by other workers. An interpretation of these patterns is given in terms of simple kinematic scatttering from flat surface regions. This leads to a straightforward interpretation of the observed specular reflection phenomenon, enables the area of coherent scattering to be estimated (0.16 μ2 in the present experiments), and should permit a more detailed analysis of ordered surface structures.