Terahertz electroluminescence of unipolar n⁺⁺-n⁻-n⁺ SiC structures at helium temperatures and I-V characteristics of bipolar n⁺⁺-π-n⁺ SiC structures with natural superlattices at 300~K at strong electrical fields are studied. The properties of the THz electroluminescence and I-V characteristics testify that these phenomena due to Bloch oscillations.