Preparation of flat surfaces on silicon carbide substrate using electron beam processing

Electron beam processing of 6H-SiC{0001} surfaces is studied. Initial substrates contain polishing scratches on (0001) face and rough surface of (000-1) face specially developed by KOH etching which are eliminated by electron beam processing. Processing is carried out in vacuum of 0.1 mTorr, energy about of 69 kJ, and background temperature of 1100 K in presence of 1-30 µm thick silicon film on the substrates. Atomic force microscopy images show near atomically flat surfaces which roughness decreases in 22-23 times for (000-1) and 1.5-2.0 times for (0001), respectively. Root-mean square value of processed surfaces are 0.27-0.30 nm for 5×5 μm2 scan area. The steps (height of 0.5-1.0 nm) between the terraces (length of 500 nm) correspond to a height of 2-4 Si-C bilayers. The obtained changing of roughness factor also indicates a decrease of real surface area of the faces during electron beam processing.