LOW-TEMPERATURE PREANNEALING FOR CARBON REMOVAL FROM SI SURFACE IN GAAS-ON-SI MOLECULAR-BEAM EPITAXIAL-GROWTH

Using Auger electron spectroscopy, quadrupole mass-spectroscopy of the desorption process, X-ray diffraction and transmission electron microscopy of molecular beam epitaxial (MBE) grown films, we compared the commonly used pregrowth thermal treatments (in the range 300 < T < 120-degrees-C) in vacuum with a new low temperature annealing procedure in hydrogen for Si (100) substrates tilted 0-degrees, 4-degrees and 9-degrees towards [011]. We showed that carbon on the Si surface suppresses the epitaxial growth of GaAs and determines the evaporation process on the Si surface. We concluded that a protective oxide layer prevented carbide formation more effectively than a hydrogen terminated layer. Using the proposed preparation technique, 1.5 mum thick MBE GaAs films on Si with a rocking curve FWHM of 10 arc min for as-grown films and 6 arc min for 20 min 850-degrees-C annealed films were produced.