THE (0001)-SURFACE OF 6H-SIC - MORPHOLOGY, COMPOSITION AND STRUCTURE

The morphology, composition and structure of wet chemically prepared 6 H-SiC(0001) samples were investigated immediately after introduction i nto vacuum. Scanning tunneling microscopy displayed large atomically f lat areas on the surface. The step structure found is correlated to th e sample periodicity normal to the surface. Most step heights are mult iples of half the vertical unit cell length. Low-energy electron diffr action (LEED) revealed good surface order with bulk-like lateral perio dicity. From high-resolution electron energy loss spectroscopy the sat uration of dangling bonds with hydroxyl species could be determined. T his termination is responsible for an electron beam sensitivity found in LEED. Upon annealing the oxygen is removed and carbon-carbon bonds develop on the surface as demonstrated by Auger electron spectroscopy. This new structure is ordered in a (root 3 X root 3)R30 degrees perio dicity.