Abstract: It is an object of the present invention to provide a silicon carbide substrate having a low defect density that does not contaminate a process device and a silicon carbide semiconductor device including the silicon carbide substrate. A silicon carbide substrate according to the present invention is a silicon carbide substrate including: a substrate inner portion; and a substrate outer portion surrounding the substrate inner portion, wherein non-dopant metal impurity concentration of the substrate inner portion is 1×1016 cm?3 or more, and a region of the substrate outer portion at least on a surface side thereof is a substrate surface region in which the non-dopant metal impurity concentration is less than 1×1016 cm?3.

Abstract: It is an object of the present invention to provide a silicon carbide substrate having a low defect density that does not contaminate a process device and a silicon carbide semiconductor device including the silicon carbide substrate. A silicon carbide substrate according to the present invention is a silicon carbide substrate including: a substrate inner portion; and a substrate outer portion surrounding the substrate inner portion, wherein non-dopant metal impurity concentration of the substrate inner portion is 1×1016 cm?3 or more, and a region of the substrate outer portion at least on a surface side thereof is a substrate surface region in which the non-dopant metal impurity concentration is less than 1×1016 cm?3.

Abstract: A semiconductor device that can suppress deterioration in crystal quality caused by a lattice mismatch between a substrate and an epitaxial layer and that also can ensure a voltage sustaining performance, and a wafer for forming the semiconductor device. An epitaxial wafer of silicon carbide (SiC), which is used for manufacturing a semiconductor device, includes a low resistance substrate and an epitaxial layer provided thereon. The epitaxial layer is doped with the same dopant as a dopant doped into the substrate, and has a laminated structure including a low concentration layer and an ultrathin high concentration layer. A doping concentration in the low concentration layer is lower than that in the silicon carbide substrate. A doping concentration in the ultrathin high concentration layer is equal to that in the silicon carbide substrate.

Abstract: A method is provided in order to manufacture a silicon carbide epitaxial wafer whose surface flatness is very good and has a very low density of carrot defects and triangular defects arising after epitaxial growth. The silicon carbide epitaxial wafer is manufactured by a first step of annealing a silicon carbide bulk substrate that is tilted less than 5 degrees from <0001> face, in a reducing gas atmosphere at a first temperature T1 for a treatment time t, a second step of reducing the temperature of the substrate in the reducing gas atmosphere, and a third step of performing epitaxial growth at a second temperature T2 below the annealing temperature T1 in the first step, while supplying at least a gas including silicon atoms and a gas including carbon atoms.

Abstract: A method is provided in order to manufacture a silicon carbide epitaxial wafer whose surface flatness is very good and has a very low density of carrot defects and triangular defects arising after epitaxial growth. The silicon carbide epitaxial wafer is manufactured by a first step of annealing a silicon carbide bulk substrate that is tilted less than 5 degrees from <0001> face, in a reducing gas atmosphere at a first temperature T1 for a treatment time t, a second step of reducing the temperature of the substrate in the reducing gas atmosphere, and a third step of performing epitaxial growth at a second temperature T2 below the annealing temperature T1 in the first step, while supplying at least a gas including silicon atoms and a gas including carbon atoms.

Abstract: A semiconductor device that can suppress deterioration in crystal quality caused by a lattice mismatch between a substrate and an epitaxial layer and that also can ensure a voltage sustaining performance, and a wafer for forming the semiconductor device. An epitaxial wafer of silicon carbide (SiC), which is used for manufacturing a semiconductor device, includes a low resistance substrate and an epitaxial layer provided thereon. The epitaxial layer is doped with the same dopant as a dopant doped into the substrate, and has a laminated structure including a low concentration layer and an ultrathin high concentration layer. A doping concentration in the low concentration layer is lower than that in the silicon carbide substrate. A doping concentration in the ultrathin high concentration layer is equal to that in the silicon carbide substrate.