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The interaction of nitrogen with 6H-SiC surfaces with different orientation and composition ranging from Si-rich to graphitized was investigated by use of X-ray and ultraviolet photoemission spectroscopy (XPS, UPS). The samples were cleaned and their surface composition was tuned by heating them in a Si flux at different temperatures or by annealing. Nitrogen exposures were performed using a RF plasma source operated at 13.56 MHz. Two different nitridation mechanisms can be distinguished by XPS. While anion exchange occurs at bulk-truncated SiC surfaces diffusion will control the nitrogen uptake of Si-rich samples. After nitridation, UPS spectra of bulk–truncated surfaces display characteristic valence-band structures of Si3N4. The thickness of the nitride layer amounts to approximately 9–12 Å. Thicker silicon nitride films on SiC are obtained by rising the sample temperature during nitrogen exposures or by deposition and subsequent nitridation of thin Si overlayers on SiC surfaces. The nitrogen uptake of graphitized samples is comparable to that of bulk-truncated surfaces. Our photoemission spectroscopy results prove that surface graphite is partly removed by N and the UPS spectra point to the formation of silicon nitride. In addition, C-N bonds exist but the exact bonding configuration cannot be resolved.