Volatile metal oxide suppression in molecular beam epitaxy systems

摘要

When growing GaAs by molecular beam epitaxy (MBE), a typical related reaction acts to affix Ga2O3 to the growth surface and hence incorporates such oxide contaminants in the epitaxial layer as it is grown. Such contaminants may yield crystals of poor electrical and optical properties. When Al is added to the Ga source crucible, the Ga2O flux is reduced substantially thereby suppressing the formation of such oxide contaminants and remove a serious constraint to MBE growth. When doping GaAs with Mg to form a p-type GaAs layer, unity Mg doping efficiency is achieved by including 0.1% Al in the Ga effusion cell. Such an inclusion of Al improves the Mg doping efficiency by suppressing the formation of MgO, and allows MBE growth at lower substrate temperatures and at higher growth rates.