Electronic and structural properties of the 6H-SiC(0001) surfaces

The atomic and electronic structures of clean 6H–SiC(0001) surfaces have been investigated by means of LEED and photoelectron spectroscopies (XPS, XAES and UPS). First a clean surface having the (3 × 3) structure has been obtained by heating the sample at 800°C under a low Si flux. Successive annealings in UHV have produced two other stable reconstructions, namely the and the . The various surface structures show distinctive core-level and Auger line shapes, which are characteristic of the composition of the surface layer, as checked by the XPS intensities by two different excitation sources (Mg Kα and Zr Mζ), while UPS spectra show sizeable differences in the character of the valence bands. The evaluation of the atomic composition is able to sort between different models proposed in the literature.