Modeling of the carbon-rich c(4 × 4) reconstruction on Si(1 0 0)

The structure and energetics of the carbon-rich c(4 × 4) surface reconstruction on Si(0 0 1) is studied theoretically. These combined analyses demonstrate that for five or six carbon atoms per c(4 × 4) unit cell, the configuration involving carbon atoms in second nearest-neighbor positions in subsurface sites is more stable than the first nearest-neighbor configuration, involving a C–C dimer and a missing Si dimer. This SiC-like configuration could account for the formation of 3C–SiC precipitates generally observed during the growth of Si–C alloys for high C concentrations (>3%) and at high temperatures (>650 °C).