FORMATION OF THE INTERFACE BETWEEN C-SI(111) AND DIAMOND-LIKE CARBON STUDIED WITH PHOTOELECTRON-SPECTROSCOPY

The hydrogen-terminated Si(111) surface was used as a substrate to gro w amorphous hydrogenated carbon (a-C:H) films by means of layer-by-lay er plasma deposition. Electronic and structural properties of the form ing interface were determined by in situ core level and valence band p hotoelectron spectroscopy. From the core level spectra the gradual for mation of an initially carbon-rich and eventually stoichiometric silic on carbide interface layer is inferred with a final thickness of 18 An gstrom. The silicon core level data indicate that the substrate is hyd rogen-passivated owing to the plasma exposure. On the final heterostru cture, the valence band edge of the diamond-like carbon is found to be 0.4 eV below that of the interfacial a-SiC:H and also below that of t he silicon, with the offset amounting to 0.7 +/- 0.1 eV. (C) 1998 Else vier Science B.V.