A structure of a GTO thyristor to which the silicon carbide semiconductor device according to the first embodiment is applied will be described as the silicon carbide semiconductor device according to a third embodiment. FIG. 13 is a cross-sectional view of a structure of the silicon carbide semiconductor device according to the third embodiment. The silicon carbide semiconductor device according to the third embodiment and depicted in FIG. 13 is a GTO thyristor to which the silicon carbide semiconductor device according to the first embodiment is applied and, for example, is fabricated (manufactured) using a semiconductor substrate 320 in which silicon carbide layers 321 to 325 constituting a first p-type layer 302, a first n-type layer 303, an n?-type drift layer 304, a second p-type layer 305, and a second n-type layer 306 are sequentially formed on a p-type starting substrate 301 by epitaxial growth.
In FIG. 13, the conductivity type of the p-type starting substrate 301 is indicated by “psub”. Doping of nitrogen as a dopant in the first n-type layer 303, the n?-type drift layer 304, and the second n-type layer 306 is indicated by “N doped”. Doping of vanadium as a dopant in the n?-type drift layer 304 is indicated by “V doped”. Doping of aluminum as a dopant in the first and the second p-type layers 302, 305 is indicated by “Al doped”. Relative lengths of carrier lifetimes of the n?-type drift layer 304 are respectively indicated by “l(fā)ong carrier lifetime” and “short carrier lifetime”.
