Abstract: A silicon carbide semiconductor substrate includes an epitaxial layer. A difference of a donor concentration and an acceptor concentration of the epitaxial layer is within a range from 1×1014/cm3 to 1×1015/cm3. Further, the donor concentration and the acceptor concentration of the epitaxial layer are a concentration unaffected by an impurity inside epitaxial growth equipment.

Abstract: A silicon carbide semiconductor substrate includes an epitaxial layer. A difference of a donor concentration and an acceptor concentration of the epitaxial layer is within a range from 1×1014/cm3 to 1×1015/cm3. Further, the donor concentration and the acceptor concentration of the epitaxial layer are a concentration unaffected by an impurity inside epitaxial growth equipment.

Abstract: A silicon carbide semiconductor substrate includes an epitaxial layer. A difference of a donor concentration and an acceptor concentration of the epitaxial layer is within a range from 1×1014/cm3 to 1×1015/cm3. Further, the donor concentration and the acceptor concentration of the epitaxial layer are a concentration unaffected by an impurity inside epitaxial growth equipment.

Abstract: A silicon carbide semiconductor device includes a silicon carbide semiconductor substrate of a first conductivity type, a first silicon carbide layer of the first conductivity type, and an insulating film. In the silicon carbide semiconductor device, no fluorine or chlorine is detectable in the insulating film, at a boundary layer of the insulating film and the first silicon carbide layer, or at the surface of first silicon carbide layer where the insulating film is provided.

Abstract: In forming an ohmic electrode on a back surface of an n-type SiC substrate, an n+-type semiconductor region is formed in a surface layer of the back surface of an n-type epitaxial substrate by ion implantation. In this ion implantation, the impurity concentration of the n+-type semiconductor region is a predetermined range and preferably a predetermined value or less, and an n-type impurity is implanted by acceleration energy of a predetermined range such that the n+-type semiconductor region has a predetermined thickness or less. Thereafter, a nickel layer and a titanium layer are sequentially formed on the surface of the n+-type semiconductor region, the nickel layer is heat treated to form a silicide, and the ohmic electrode formed from nickel silicide is formed. In this manner, a back surface electrode that has favorable properties can be formed while peeling of the back surface electrode can be suppressed.

Abstract: A method of manufacturing a silicon carbide semiconductor device includes forming a first silicon carbide layer of a first conductivity type on a front surface of a silicon carbide semiconductor substrate. A thermal oxidation film is formed on a surface of a base body including the first silicon carbide layer. The thermal oxidation film is subsequently removed using a solution containing hydrofluoric acid. The base body is washed with a mixture of ammonia water and a hydrogen peroxide solution, a mixture of hydrochloric acid and a hydrogen peroxide solution, and a dilute hydrofluoric acid. The base body is held at temperature of 700 degrees C. to 1700 degrees C., and an insulating film is deposited on the base body.

Abstract: A vertical MOSFET having a trench gate structure includes an n?-type drift layer and a p-type base layer formed by epitaxial growth. In the p-type base layer, an n+-type source region is provided. A trench that penetrates the p-type base layer and the n+-type source region, and reaches the n?-type drift layer is provided. The first p+-type region is in contact with a bottom of the trench and is implanted with an impurity that determines a conductivity type of the first p+-type region and a first element that bonds with a second element that is displaced by the impurity, the impurity and the second element being implanted at a predetermined ratio.

Abstract: A titanium layer and a nickel layer are sequentially formed on a back surface of a SiC wafer. Next, by high-temperature heat treatment, the SiC wafer is heated and the titanium layer and the nickel layer are sintered forming a nickel silicide layer that includes titanium carbide. By this high-temperature heat treatment, an ohmic contact of the SiC wafer and the nickel silicide layer is formed. Thereafter, on the nickel silicide layer, a back surface electrode multilayered structure is formed by sequentially stacking a titanium layer, a nickel layer, and a gold layer. Here, in forming the nickel layer that configures a back surface electrode multilayered structure, the nickel layer is formed under a condition that satisfies 0.0<y<?0.0013x+2.0, where the thickness of the nickel layer is x [nm] and the deposition rate of the nickel layer is y [nm/second]. Thus, peeling of the back surface electrode can be suppressed.

Abstract: A method of manufacturing a silicon carbide semiconductor device includes forming a first silicon carbide layer of a first conductivity type on a front surface of a silicon carbide semiconductor substrate. A thermal oxidation film is formed on a surface of a base body including the first silicon carbide layer. The thermal oxidation film is subsequently removed using a solution containing hydrofluoric acid. The base body is washed with a mixture of ammonia water and a hydrogen peroxide solution, a mixture of hydrochloric acid and a hydrogen peroxide solution, and a dilute hydrofluoric acid. The base body is held at temperature of 700 degrees C. to 1700 degrees C., and an insulating film is deposited on the base body.

Abstract: A silicon carbide semiconductor device includes a silicon carbide semiconductor substrate of a first conductivity type, a first silicon carbide layer of the first conductivity type, and an insulating film. In the silicon carbide semiconductor device, no fluorine or chlorine is detectable in the insulating film, at a boundary layer of the insulating film and the first silicon carbide layer, or at the surface of first silicon carbide layer where the insulating film is provided.

Abstract: An impurity of a second conductivity type is selectively doped in a surface of a semiconductor substrate of a first conductivity type to form doped regions. A portion of a surface of the doped regions is covered by a heat insulating film. At least a remaining portion of the surface of the doped regions is covered by an absorbing film and the doped regions are heated through the absorbing film, enabling an impurity region of the second conductivity type to be formed having two or more of the doped regions that have a same impurity concentration and differing carrier concentrations.

Abstract: After a titanium nitride film is formed to cover an interlayer insulating film, a first nickel film is formed on a front surface of a silicon carbide base exposed in a contact hole, so as to extend on the titanium nitride film. Next, the silicon carbide base and the first nickel film are reacted by rapid thermal annealing at a temperature of 800 to 1100 degrees C. to form a nickel silicide film that forms an ohmic contact. Grains of the titanium nitride film are enlarged by the rapid thermal annealing, making a grain size of the titanium nitride film 20 nm to 50 nm. Thus, interstices of the grains of the titanium nitride film become smaller than before the rapid thermal annealing or are eliminated, enabling the intrusion of nickel from the first nickel film into the interstices of the columnar grains of the titanium nitride film to be suppressed.

Abstract: An impurity of a second conductivity type is selectively doped in a surface of a semiconductor substrate of a first conductivity type to form doped regions. A portion of a surface of the doped regions is covered by a heat insulating film. At least a remaining portion of the surface of the doped regions is covered by an absorbing film and the doped regions are heated through the absorbing film, enabling an impurity region of the second conductivity type to be formed having two or more of the doped regions that have a same impurity concentration and differing carrier concentrations.

Abstract: An impurity of a second conductivity type is selectively doped in a surface of a semiconductor substrate of a first conductivity type to form doped regions. A portion of a surface of the doped regions is covered by a heat insulating film. At least a remaining portion of the surface of the doped regions is covered by an absorbing film and the doped regions are heated through the absorbing film, enabling an impurity region of the second conductivity type to be formed having two or more of the doped regions that have a same impurity concentration and differing carrier concentrations.

Abstract: A silicon carbide semiconductor substrate includes an epitaxial layer. A difference of a donor concentration and an acceptor concentration of the epitaxial layer is within a range from 1×1014/cm3 to 1×1015/cm3. Further, the donor concentration and the acceptor concentration of the epitaxial layer are a concentration unaffected by an impurity inside epitaxial growth equipment.

Abstract: A silicon carbide semiconductor device includes an n+-type SiC substrate, a gate oxide film formed on a portion of the surface of the n+-type SiC substrate, a gate electrode formed on the gate oxide film, an interlayer insulating film formed so as to cover the gate electrode, a TiN film formed so as to cover the interlayer insulating film, and a Ni silicide layer formed on a surface of the n+-type SiC substrate not covered by the interlayer insulating film. The TiN film has two or more layers.

Abstract: A silicon carbide semiconductor device includes an n+-type SiC substrate, a gate oxide film formed on a portion of the surface of the n+-type SiC substrate, a gate electrode formed on the gate oxide film, an interlayer insulating film formed so as to cover the gate electrode, a TiN film formed so as to cover the interlayer insulating film, and a Ni silicide layer formed on a surface of the n+-type SiC substrate not covered by the interlayer insulating film. The TiN film has two or more layers.

Abstract: An impurity of a second conductivity type is selectively doped in a surface of a semiconductor substrate of a first conductivity type to form doped regions. A portion of a surface of the doped regions is covered by a heat insulating film. At least a remaining portion of the surface of the doped regions is covered by an absorbing film and the doped regions are heated through the absorbing film, enabling an impurity region of the second conductivity type to be formed having two or more of the doped regions that have a same impurity concentration and differing carrier concentrations.

Abstract: After a titanium nitride film is formed to cover an interlayer insulating film, a first nickel film is formed on a front surface of a silicon carbide base exposed in a contact hole, so as to extend on the titanium nitride film. Next, the silicon carbide base and the first nickel film are reacted by rapid thermal annealing at a temperature of 800 to 1100 degrees C. to form a nickel silicide film that forms an ohmic contact. Grains of the titanium nitride film are enlarged by the rapid thermal annealing, making a grain size of the titanium nitride film 20 nm to 50 nm. Thus, interstices of the grains of the titanium nitride film become smaller than before the rapid thermal annealing or are eliminated, enabling the intrusion of nickel from the first nickel film into the interstices of the columnar grains of the titanium nitride film to be suppressed.

Abstract: A method of manufacturing a silicon carbide semiconductor device includes grinding a back surface of a semiconductor substrate formed of silicon carbide to reduce thickness thereof and provide an altered layer that is ground; removing by polishing or etching, the altered layer from the back surface; forming a nickel film on the back surface of the semiconductor substrate after removing the altered layer; heat treating the nickel film to forming a nickel silicide layer by silicidation; and forming a metal electrode on a surface of the nickel silicide layer.