CARBON INCORPORATION IN SI1-YCY ALLOYS GROWN BY MOLECULAR-BEAM EPITAXY USING A SINGLE SILICON-GRAPHITE SOURCE

Pseudomorphic Si1-yCy alloys on silicon (100) were grown by molecular beam epitaxy using a single effusion source of silicon contained in a graphite crucible, producing carbon concentrations of y = 0.008. The b ehavior of carbon incorporation using this source was studied as a fun ction of growth temperature using x-ray diffraction and infrared spect roscopy, and was compared to previous studies, where Si1-yCy was grown from separate silicon and graphite sources. An increased energy barri er for the surface diffusion of carbon was observed using the single s ilicon-graphite source. An infrared absorption mode near 725 cm(-1), o bserved for growth temperatures up to 700 degrees C, was attributed to a transitional phase between the loss of substitutional carbon and th e formation of silicon carbide precipitates. (C) 1998 American Institu te of Physics.