Initial stages in the carbonization of (111)Si by solid-source molecular beam epitaxy

Silicon carbide can be reproducibly grown on (111)Si below 600 degrees C by carbonization using an elemental solid carbon source in molecular beam epitaxy. The initial stages were observed by in situ reflection high-energy electron diffraction. Prior to silicon carbide growth, the continuous carbon flux lead to a transition from the (7 X 7) reconstruction of clean (111)Si to a carbon-induced (root 3 x root 3)R30 degrees structure. Above 660 degrees C, the silicon carbide growth starts directly on the silicon surface via three-dimensional nucleation. Below 660 degrees C, first a thin silicon-carbon alloy was formed by diffusion of carbon into the surface near the region with a concentration exceeding the bulk solubility in silicon. (C) 1998 American Institute of Physics. [S0003-6951(98)00350-7].