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 behavior of carbon incorporation using this source was studied as a function of growth temperature using x-ray diffraction and infrared spectroscopy, and was compared to previous studies, where Si1-yCy was grown from separate silicon and graphite sources. An increased energy barrier for the surface diffusion of carbon was observed using the single silicon-graphite source. An infrared absorption mode near 725 cm(-1), observed for growth temperatures up to 700 degrees C, was attributed to a transitional phase between the loss of substitutional carbon and the formation of silicon carbide precipitates. (C) 1998 American Institute of Physics.