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Basic experimental results obtained for the low-temperature molecular beam epitaxy with atomic hydrogen have been presented. GaAs films grown at different substrate temperatures have exhibited different values of dislocation densities and the average dislocation density as low as 3×104 cm−2 has been successfully obtained for the films grown at a low-temperature of 330 °C with atomic hydrogen irradiation. These are among the lowest dislocation values reported to date. The surface cleaning effects and reconstruction of vicinal Si(100) surfaces during the atomic hydrogen irradiation, and also the electrical properties of epitaxial films have been investigated and analyzed. Physics behind the drastic dislocation density reduction has been investigated in detail based on the results of cross-sectional and plan-view transmission electron microscope observations and analysis of the growth kinetics.

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.

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