A semiconductor device is manufactured by implanting impurity ions in one surface of a semiconductor substrate made of silicon carbide; irradiating a region of the semiconductor substrate implanted with the impurity ions with laser light of a wavelength in the ultraviolet region; and forming, on a surface of a high-concentration impurity layer formed by irradiating with the laser light, an electrode made of metal in ohmic contact with the high-concentration impurity layer. When irradiating with the laser light, a first concentration peak of the impurity ions that exceeds a solubility limit concentration of the impurity ions in silicon carbide is formed in a surface region near the one surface of the semiconductor substrate within the high-concentration impurity layer.

A silicon carbide semiconductor device, including a semiconductor substrate having first and second semiconductor regions and a plurality of third semiconductor regions sequentially formed therein, a plurality of trenches penetrating the second and third semiconductor regions, a plurality of gate electrodes provided in the trenches via a gate insulating film, an interlayer insulating film covering the gate electrodes, a plurality of contact holes penetrating the interlayer insulating film, a first electrode provided in the contact holes and at the surface of the interlayer insulating film, and a second electrode electrically connected to the first semiconductor region. The interlayer insulating film has a plurality of recessed parts and protruding parts, to thereby form at least three recesses and protrusions repeatedly at a surface of the interlayer insulating film. The first electrode includes first to third electrode films, the second electrode film having a shape reflecting the surface of the interlayer insulating film.

A method of forming a contact structure includes providing a silicon-carbide substrate having a highly doped silicon-carbide contact region formed in the substrate and extending to a main surface of the substrate. A carbon-based contact region is formed which is in direct contact with the highly doped silicon-carbide contact region and which extends to the main surface. A conductor is formed on the carbon-based contact region such that the carbon-based contact region is interposed between the conductor and the highly doped silicon-carbide contact region. A thermal budget for forming the carbon-based contact region is maintained below a level that induces metal silicidization of the highly doped silicon-carbide contact region.

A semiconductor device according to an embodiment includes: a first electrode; a SiC semiconductor layer including n-type semiconductor; and a second electrode including a SiC metallic region made of metal in contact with the SiC semiconductor layer, the SiC metallic region provided on a side of the SiC semiconductor layer opposite to the first electrode, the SiC metallic region containing at least one element selected from the group of Mg (magnesium), Ca (calcium), Sr (strontium), Ba (barium), Sc (scandium), Y (yttrium), La (lanthanum), and lanthanoid (Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu).

A method of manufacturing a silicon carbide semiconductor device, having a silicon carbide semiconductor element substrate and a surface electrode film forming an ohmic contact between them. A first electrode film including nickel is formed on the substrate surface. A second electrode film with nickel silicide is formed on a first electrode film surface. The surface film is formed having the ohmic contact between the substrate surface and the first electrode film by annealing to cause silicon of the substrate and nickel of the first electrode film to react and convert the first electrode film to silicide. The first electrode film is formed with a thickness so that during annealing, an amount of carbon atoms is liberated from the substrate and diffuses toward the first electrode film, wherein the liberated amount is equal to or less than the amount of carbon atoms that the second electrode film is able to take in during annealing.

A semiconductor device of according to an embodiment of the present disclosure includes a n-type SiC layer; a SiC region provided on the n-type SiC layer and containing H (hydrogen) or D (deuterium) in an amount of 1×10.sup.18 cm.sup.−3 or more and 1×10.sup.22 cm.sup.−3 or less; and a metal layer provided on the SiC region.

The silicon carbide layer has a second main surface. The second main surface has a peripheral region within 5 mm from an outer edge thereof, and a central region surrounded by the peripheral region. The silicon carbide layer has a central surface layer. An average value of a carrier concentration in the central surface layer is not less than 1×10.sup.14 cm.sup.−3 and not more than 5×10.sup.16 cm.sup.−3. Circumferential uniformity of the carrier concentration is not more than 2%, and in-plane uniformity of the carrier concentration is not more than 10%. An average value of a thickness of a portion of the silicon carbide layer sandwiched between the central region and the silicon carbide single-crystal substrate is not less than 5 μm. Circumferential uniformity of the thickness is not more than 1%, and in-plane uniformity of the thickness is not more than 4%.

Provided are a method of processing a semiconductor substrate and a method of manufacturing a semiconductor device that uses this method of processing. The method of processing the semiconductor substrate includes: a bonding step in which a supporting plate, which is composed primarily of a material that substantially transmits laser light of prescribed wavelength, and a principal surface of a semiconductor substrate, which is composed primarily of a material that substantially transmits the laser light of the prescribed wavelength, are arranged to face each other in a vacuum and then pressed together in the vacuum with an intermediate layer that includes an amorphous silicon layer interposed therebetween; and a separating step in which, after the laser light is radiated from a side of the supporting plate and the intermediate layer absorbs laser energy, the semiconductor substrate and the supporting plate are separated from each other.

A semiconductor device according to an embodiment includes a first-conductivity-type SiC substrate, a first-conductivity-type SiC layer provided on the SiC substrate, having a first surface, and having a lower first-conductivity-type impurity concentration than the SiC substrate, first second-conductivity-type SiC regions provided in the first surface of the SiC layer, second second-conductivity-type SiC regions provided in the first SiC regions and having a higher second-conductivity-type impurity concentration than the first SiC region, silicide layers provided on the second SiC regions and having a second surface, a difference between a distance from the SiC substrate to the second surface and a distance from the SiC substrate to the first surface being equal to or less than 0.2 μm, a first electrode provided to contact with the SiC layer and the silicide layers, and a second electrode provided to contact with the SiC substrate.

A method for manufacturing a silicon carbide semiconductor device includes preparing a silicon carbide layer including an n-type region having an n conductivity type and a p-type region having a p conductivity type, forming a material layer containing titanium, aluminum, and silicon on the n-type region and the p-type region, and forming an electrode layer in contact with the n-type region and the p-type region by heating the material layer. In forming a material layer, composition of the material layer is determined such that a point (x, y, z) (x, y, and z each being a numeric value greater than 0) representing a composition ratio among titanium, aluminum, and silicon is included in a first triangular pyramidal region having four points of the origin (0, 0, 0), a point (1, 2, 2), a point (2, 1, 2) and a point (2, 2, 1) as vertices.