STM and LEED observation of hydrogen adsorption on the 6H–SiC(0 0 0 1)3×3 surface

We have investigated the hydrogen adsorption and hydrogen-induced structural deformation at a 6H–SiC(0 0 0 1)3×3 surface by scanning tunneling microscopy (STM) and low-energy electron diffraction (LEED). The 3×3 surface obtained by Si deposition followed by annealing at 750°C is revealed to contain C atoms as its constituent. At relatively low hydrogen exposures of the 3×3 surface, atoms in the topmost layer are displaced, where 3×3 periodicity of the surface is preserved. With heavier dosages of hydrogen, the second and the third layers of the 3×3 surface are also disintegrated, being accompanied with degradation of fractional order spots in the 3×3 LEED pattern.