Structural reorganisation of vicinal surfaces on 6H-SiC(0001) induced by hot hydrogen etching

An extended set of vicinal surfaces has been prepared in a 6H-SiC(0001) substrate by mechanically grinding a concave-shaped surface, followed by hot hydrogen etching. During grinding, the different crystallographic planes building up the 6H-SiC polytype are cut under continuously changing polar angles in all azimuthal directions. The local structural reorganisation under hot hydrogen etching is studied by scanning electron microscopy (SEM). The etching conditions for silicon carbide concave-shaped surfaces with vicinal orientations close to (0001) are investigated. Results of hydrogen etching for substrate temperatures of 1700 and 1800degreesC are presented. Two types of local bond environments are created, leading to a strong anisotropy of the hydrogen etching. Stable step alignments are observed along the (11 (2) over bar0) crystallographic directions, which reflect the symmetry of the bonding of the material. The polar variations of the surface orientation within the concave-shaped surface leads to a variation of the terrace widths with smaller terraces obtained for larger polar misfit. (C) 2004 Elsevier B.V. All rights reserved.