Ex Situ and In Situ Methods for Complete Oxygen and Non-Carbidic Carbon Removal from (0001)_SI 6H-SiC Surfaces

Abstract

Comparisons between the wetting characteristics of (0001)si 6H-SiC and (111) Si surfaces in various acids and bases were made. It was found that 10:1 HF dipped Si (111) surfaces were hydrophobic where as the (0001)si 6H-SiC surfaces were hydrophilic. (0001)si 6H-SiC surfaces capped with a 20A Si layer, however, were hydrophobic after HF dipping and exhibited outgassing levels on annealing which were several orders of magnitude lower than SiC wafers dipped in HF without the capping layer. Annealing the Si capped (0001)si 6H-SiC surfaces in UHV at 1 100*C for 5 min. was found to be sufficient to thermally desorb the Si capping layer and produce a (3x3) Si rich, oxygen free (0001),i 6H-SiC surface.