PES and LEED study of hydrogen- and oxygen-terminated 6H–SiC(0 0 0 1) and (0 0 0 1̄) surfaces

We have studied the effect of a wet-chemical cleaning procedure and a thermal hydrogen treatment on Si-terminated 6H–SiC(0 0 0 1) and C-terminated 6H–SiC(0 0 0 1̄) surfaces by photoelectron spectroscopy and low-energy electron diffraction (LEED). On SiC(0 0 0 1), the different steps of the wet-chemical treatment result in oxygen-contaminated surfaces with a monolayer of Si+ due to hydroxyl groups. The first step of the wet-chemical treatment also produces Si4+ accompanied by a (3×3)R30° LEED pattern, indicating the presence of areas terminated by a silicate adlayer on the surface. Annealing of SiC(0 0 0 1) and SiC(0 0 0 1̄) surfaces in molecular hydrogen at temperatures around 1000 °C removes surface oxygen and results in H-terminated surfaces with (1×1) periodicity, which are electronically and chemically passivated.