4H-SiC single crystals have been deformed under 5 GPa at room temperature and 150degreesC using an anisotropic multi-anvil apparatus. Transmission Electron Microscopy observations show that the microstructure is composed of widely dissociated dislocations and perfect dislocations. The generation of such perfect dislocations could indicate that silicon carbide exhibits a change in deformation mechanism under very high stress, with a behavior similar to Si and III-V compounds.