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Low Dislocation Density GaAs on Vicinal Si(100) Grown by Molecular Beam Epitaxy with Atomic Hydrogen Irradiation

This work describes a novel technique for reducing the dislocation density of GaAs grown on Si(100). Atomic hydrogen has been irradiated for both the surface cleaning stage of the substrate prior to and during the growth by the conventional molecular beam epitaxy (MBE). Effects of atomic hydrogen irradiation at the Si surface cleaning stage shows that not only clean single domain surfaces can be obtained below 700°C, which is much lower than the normal surface preparation temperature, but also results in a drastic reduction of the dislocation density in the GaAs films. The epitaxial films grown at different substrate temperatures have exhibited different values of dislocation densities as determined by etch pit density (EPD) measurements, and the average density of as low as 7×104 cm-2 has been obtained for GaAs films grown at low-temperature of 330°C.