The surface morphology of Si (100) after carbon deposition

The concentration of carbon in thin epitaxial layers is thought to be above the solution limit if special epitaxial conditions apply [H. Rucker, M. Methfessel, E. Bugiel, H.J. Osten, Phys. Rev. Lett. B 72 (1994) 3578]. Depending on those conditions the structure and morphology of carbon deposited on Si(100) at 600 degrees C has been studied by means of scanning tunnelling microscopy and low energy electron diffraction. At carbon coverages below 1/2 monolayer (ML) a c(4 x 4) structure is obtained. Higher carbon coverages (up to 1 ML) give rise to island formation and a 2 x 1 structure of the substrate surface. The surface morphology of subsequent Si depositions depends on the initial carbon concentration. The c(4 x 4) structure (without islands) can be observed even after an additional epitaxial Si layer 3 nm thick is deposited. The Si epitaxy on carbon layers with islands leads to a patchwise growth process resulting in surfaces with etch pit-like defects. (C) 1998 Elsevier Science B.V. All rights reserved.