GROWTH OF SI/GAAS SUPERLATTICES BY MOLECULAR-BEAM EPITAXY

The growth and characterization of a ten period silicon/GaAs superlattice by molecular beam epitaxy is described. Reflection high energy electron diffraction of the surface reconstruction during growth of the GaAs layers showed the (4 X 2) --> (3 X 2) --> (3 X 1) --> (2 X 4) sequence reported previously for GaAs grown on pseudomorphic silicon, although the intermediate stages were much more persistent than previously reported. X-ray diffraction revealed satellite peaks clearly visible out to the fourth order, indicating a high degree of structural perfection. Comparison of the experimental diffraction profile and that obtained using a dynamical diffraction simulation yielded average layer thicknesses of 440 and 2.7 angstrom for the GaAs and silicon layers, respectively. Excellent agreement between the experimental and the simulated profiles was observed.