A semiconductor device of an embodiment includes: a first trench in a silicon carbide layer and extending in a first direction; a second trench and a third trench located in a second direction orthogonal to the first direction with respect to the first trench and adjacent to each other in the first direction, n type first silicon carbide region, p type second silicon carbide region on the first silicon carbide region, n type third silicon carbide region on the second silicon carbide region, p type fourth silicon carbide region between the first silicon carbide region and the second trench, and p type fifth silicon carbide region located between the first silicon carbide region and the third trench; a gate electrode in the first trench; a first electrode; and a second electrode. A part of the first silicon carbide region is located between the second trench and the third trench.

A method for manufacturing a silicon carbide substrate includes steps of preparing a silicon carbide substrate having a main surface, polishing the main surface of the silicon carbide substrate using a polishing agent containing a metal catalyst, and cleaning the silicon carbide substrate after the step of polishing. The step of cleaning includes a step of cleaning the silicon carbide substrate with aqua regia.

A semiconductor device of the present invention includes a semiconductor layer, a gate trench that defines a source region of a first conductivity type in the semiconductor layer, a channel region of a second conductivity type of a lower part of the source region, a source trench that passes through the source region and the channel region, an impurity region of the second conductivity type of a bottom part and a side part of the source trench, a source electrode on the semiconductor layer, and a highly-concentrated impurity region of the second conductivity type, the highly-concentrated impurity region having a contact portion connected to the source electrode at a surface of the semiconductor layer, the highly-concentrated impurity region passing through the source region and extending to a position deeper than the source region, the highly-concentrated impurity region having a concentration higher than the impurity region.

Semiconductor devices and methods of forming a semiconductor device that includes a deep shielding pattern that may improve a reliability and/or a functioning of the device. An example method may include forming a wide band-gap semiconductor layer structure on a substrate, the semiconductor layer structure including a drift region that has a first conductivity type; forming a plurality of gate trenches in an upper portion of the semiconductor layer structure, the gate trenches spaced apart from each other, each gate trench having a bottom surface, a first sidewall, a second sidewall, and an upper opening; forming an obstruction over a portion of each gate trench that partially obscures the upper opening; and implanting dopants having a second conductivity type that is opposite the first conductivity type into the bottom surfaces of the gate trenches, where the dopants implanted into the bottom surface of the gate trenches form deep shielding patterns.

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 of metal-assisted chemical etching comprises forming an array of discrete metal features on a surface of a semiconductor structure, where each discrete metal feature comprises a porous metal body with a plurality of pores extending therethrough and terminating at the surface of the semiconductor structure. The semiconductor structure is exposed to an etchant, and the discrete metal features sink into the semiconductor structure as metal-covered surface regions are etched. Simultaneously, uncovered surface regions are extruded through the pores to form anchoring structures for the discrete metal features. The anchoring structures inhibit detouring or delamination of the discrete metal features during etching. During continued exposure to the etchant, the anchoring structures are gradually removed, leaving an array of holes in the semiconductor structure.

A semiconductor apparatus has a silicon carbide substrate heavily doped with the first conductivity type and a lightly doped silicon carbide drift region of the first conductivity type over the silicon carbide substrate. A first body region in the drift region is doped with second conductivity type opposite the first. A first source region in the first body region is heavily doped with the first conductivity type. A gate trench is formed in the first source region and first body region. At least one sidewall of the gate trench is parallel to a crystal plane of the silicon carbide structure having greater carrier mobility than a C-face thereof. The gate trench extends a length of the first body region and the source region to a separation region laterally adjacent to the first region wherein the separation region is in the drift region.

Provided is a method for manufacturing a thin SiC wafer by which a SiC wafer is thinned using a method without generating crack or the like, the method in which polishing after adjusting the thickness of the SiC wafer can be omitted. The method for manufacturing the thin SiC wafer 40 includes a thinning step. In the thinning step, the thickness of the SiC wafer 40 can be decreased to 100 μm or less by performing the Si vapor pressure etching in which the surface of the SiC wafer 40 is etched by heating the SiC wafer 40 after cutting out of an ingot 4 under Si vapor pressure.

A silicon carbide epitaxial layer includes: a first impurity region; a second impurity region; and a third impurity region. A gate insulating film is in contact with the first impurity region, the second impurity region, and the third impurity region. A groove portion is formed in a surface of the first impurity region, the surface being in contact with the gate insulating film, the groove portion extending in one direction along the surface, a width of the groove portion in the one direction being twice or more as large as a width of the groove portion in a direction perpendicular to the one direction, a maximum depth of the groove portion from the surface being not more than 10 nm.

A semiconductor device includes an N-type silicon carbide layer, a P-type region, an N-type source region, a P-type contact region, a gate insulating film, a gate electrode, and a source electrode on the front surface side of an N-type silicon carbide substrate. A drain electrode is located on the back surface of the N-type silicon carbide substrate. A life time killer introduction region is located along an entire interface of the N-type silicon carbide layer and the bottom face of the P-type region. The life time killer is introduced by implanting helium or protons from the back surface side of the N-type silicon carbide substrate after forming a surface structure of an element on the front surface side of the N-type silicon carbide substrate and before forming the drain electrode.