Silicon carbide semiconductor device and method of manufacturing silicon carbide semiconductor device

Abstract

On a front surface of an n-type starting substrate containing silicon carbide, a pin diode is configured having silicon carbide layers constituting an n-type buffer layer, an n-type drift layer, and a p-type anode layer sequentially formed by epitaxial growth. The n-type buffer layer is formed by so-called co-doping of nitrogen and vanadium, which forms a recombination center, together with an n-type impurity. The n-type buffer layer includes a first part disposed at a side of a second interface of the buffer layer with the substrate and a second part disposed at side of a first interface of the buffer layer with the drift layer. The vanadium concentration in the second part is lower than that in the first part. The vanadium concentration in the second part is at most one tenth of the maximum value Vmax of the vanadium concentration in the n-type buffer layer.