REFLECTION HIGH-ENERGY ELECTRON-DIFFRACTION OF HETEROEPITAXY IN CHEMICAL VAPOR-DEPOSITION REACTOR - ATOMIC-LAYER EPITAXY OF GAAS, ALAS AND GAP ON SI

We developed an observation technique of reflection high-energy electron diffraction (RHEED) for chemical vapor deposition (CVD). Using this technique, growth procedures of GaAs, AlAs and GaP on Si substrates, including thermal cleaning of Si, prelayer deposition and initial stage of growth, were examined. The growth was done applying atomic layer epitaxy in a CVD reactor. Then the origin of three-dimensional island growth on Si was studied. To separate the effects of lattice mismatch and those originating from the Si surface, growth of GaAs/GaP and GaP/GaAs was also examined. We concluded that the island growth at the initial stage was not directly induced by the lattice mismatch but by unintentional adsorption of intrinsic atoms onto the Si surface. The surface morphology was improved by depositing a prelayer at an optimum temperature of 850-degrees-C and growing an AlAs buffer layer.