Reactive ion etching (RIE) of GH-SC in fluorinated plasmas, such as CF4 and SF6 with oxygen and nitrogen addition, has been investigated. Extreme anisotropic mesa structures necessary for p-n diodes were fabricated. The influence of oxygen and nitrogen gas flow on etching rates and selectivity to Si was examined. For the pure CF4 system etching rates were very small, whereas in pure SF6 the results were relatively high (probably due to the higher reactivity of S). As expected the etching rates increase drastically in CF4 with the addition of O-2; in SF6 the behavior is more complicated. The addition of N-2 to CF4/O-2 plasmas largely enhances the etching rate, whereas in SF6/O-2 the etching rates decrease with N-2 addition due to formation of complex molecules under F participation. A selectivity higher than unity for the SiC:Si system was observed for oxygen flows higher than 25 seem (CF4/N-2) and 60 seem (SF6/N-2). The etching rate of SiC depends linearly on applied RF power in CF4; nitrogen addition enhances etching by a factor of approximately 1.4. In SF6 nitrogen has only minor effects on etching rates but for applied RF powers higher than 200 W the etching rates increase strongly, indicating a change in plasma chemistry more suitable for SiC etching. Atomic force microscopy proved the usefulness of RIE for surface preparation, like polishing damage removal and smoothing for oxidation or epitaxy. Anisotropic etching behavior of the C- and Si-face of SiC samples under certain plasma conditions give way to the formulation of a new three-step etching model for RIE of SiC.