Surface topography of the (0001) facet plane of as-grown 6H-SiC bulk crystals was observed ex-situ by Nomarski optical microscopy (NOM) and atomic force microscopy (AFM). NOM observations revealed giant steps of a few micrometers in height on the (0001) growth facet, and it was found that a morphological transition of the growth facet occurred when the growth conditions were changed. AFM imaging of the stepped structure of 6H-SiC(0001) detected steps of height equal to the unit c-lattice parameter. They are fairly straight and very regularly arranged, giving rise to equidistant step trains. Upon nitrogen doping, these regular step trains on the 6H-SiC(0001)C surfaces became unstable: the equidistant step trains were transformed into meandering macrosteps of height greater than 10nm.