A bipolar structure which is arranged to conduct current between a first ohmic contact and a second ohmic contact comprising: a n-type silicon carbide substrate (31; 602; 702; 802) having a thickness of at least 125 micrometers and a doping concentration of between about 5 x 10 18 and 2 x 10 19 cm -3; a n+ epitaxial buffer layer (32; 604; 704; 804) of silicon carbide on said silicon carbide substrate (31; 602; 702; 802); a n- epitaxial voltage blocking layer (33; 606; 706; 806) of silicon carbide on said n+ epitaxial layer (32; 604; 704; 804); and a p+ epitaxial layer (34; 608; 708; 808) of silicon carbide on said n- epitaxial voltage blocking layer (33; 606; 706; 806); wherein the n- epitaxial voltage blocking layer (33; 606; 706; 806) has a thickness that is defined by a maximum reverse blocking voltage and a doping concentration of said n- epitaxial voltage blocking region (33; 606; 706; 806) is selected such that the n- epitaxial voltage blocking region (33; 606; 706; 806) is completely depleted under the maximum reverse blocking voltage; the n- epitaxial voltage blocking layer (33; 606; 706; 806) is between and directly contacting both the n+ epitaxial buffer layer (32; 604; 704; 804) and the p+ epitaxial layer (34; 608; 708; 808); the n+ epitaxial buffer layer (32; 604; 704; 804) has a thickness greater than the hole diffusion length in the n+ epitaxial buffer layer (32; 604; 704; 804); said p+ epitaxial layer (34; 608; 708; 808) has a thickness greater than the electron diffusion length in the said p+ epitaxial layer (34; 608; 708; 808); said p+ epitaxial layer (34; 608; 708; 808) has a carrier concentration of about two orders of magnitude greater than the n- epitaxial voltage blocking layer; wherein the first ohmic contact is made on the p+ epitaxial layer (34; 608; 708; 808) and the second ohmic contact is made on the substrate (31; 602; 702; 802); wherein a first interface is formed by the physical boundary between the n+ epitaxial buffer layer (32; 604; 704; 804) and the substrate (31; 602; 702; 802); and wherein a second interface is formed by the physical boundary between the first ohmic contact and the p+ epitaxial layer (34; 608; 708; 808). a n-type silicon carbide substrate (31; 602; 702; 802) having a thickness of at least 125 micrometers and a doping concentration of between about 5 x 10 18 and 2 x 10 19 cm -3; a n+ epitaxial buffer layer (32; 604; 704; 804) of silicon carbide on said silicon carbide substrate (31; 602; 702; 802); a n- epitaxial voltage blocking layer (33; 606; 706; 806) of silicon carbide on said n+ epitaxial layer (32; 604; 704; 804); and a p+ epitaxial layer (34; 608; 708; 808) of silicon carbide on said n- epitaxial voltage blocking layer (33; 606; 706; 806); wherein the n- epitaxial voltage blocking layer (33; 606; 706; 806) has a thickness that is defined by a maximum reverse blocking voltage and a doping concentration of said n- epitaxial voltage blocking region (33; 606; 706; 806) is selected such that the n- epitaxial voltage blocking region (33; 606; 706; 806) is completely depleted under the maximum reverse blocking voltage; the n- epitaxial voltage blocking layer (33; 606; 706; 806) is between and directly contacting both the n+ epitaxial buffer layer (32; 604; 704; 804) and the p+ epitaxial layer (34; 608; 708; 808); the n+ epitaxial buffer layer (32; 604; 704; 804) has a thickness greater than the hole diffusion length in the n+ epitaxial buffer layer (32; 604; 704; 804); said p+ epitaxial layer (34; 608; 708; 808) has a thickness greater than the electron diffusion length in the said p+ epitaxial layer (34; 608; 708; 808); said p+ epitaxial layer (34; 608; 708; 808) has a carrier concentration of about two orders of magnitude greater than the n- epitaxial voltage blocking layer; wherein the first ohmic contact is made on the p+ epitaxial layer (34; 608; 708; 808) and the second ohmic contact is made on the substrate (31; 602; 702; 802); wherein a first interface is formed by the physical boundary between the n+ epitaxial buffer layer (32; 604; 704; 804) and the substrate (31; 602; 702; 802); and wherein a second interface is formed by the physical boundary between the first ohmic contact and the p+ epitaxial layer (34; 608; 708; 808).