A method for producing an ohmic contact on a crystallographic C-side of a silicon carbide substrate. The method includes: applying a layer stack to the crystallographic C-side of the silicon carbide substrate, the layer stack including at least one semiconducting layer containing germanium, and at least one metallic layer; and producing a point-by-point liquid phase of the layer stack, a surface of the layer stack being scanned using laser beams.

In an entire intermediate region between an active region and an edge termination region, a p.sup.+-type region is provided between a p-type base region and a parallel pn layer. The p.sup.+-type region is formed concurrently with and in contact with p.sup.+-type regions for mitigating electric field near bottoms of gate trenches. The p.sup.+-type region has portions that face, respectively, n-type regions and p-type regions of a parallel pn layer in a depth direction Z and at the portions, has protrusions that protrude toward the parallel pn layer. N-type current spreading regions extend in the entire intermediate region from the active region and are between the p.sup.+-type region and the parallel pn layer, positioned between protrusions of the p.sup.+-type region. The impurity concentration of the n-type current spreading regions in the gate region is higher than that of those in other regions. Thus, avalanche capability may be enhanced.

A transistor device and a method for forming a transistor device are disclosed. The transistor device includes: a SiC semiconductor body that includes a first semiconductor layer and a second semiconductor layer formed on top of the first semiconductor; a trench structure extending from a first surface of the semiconductor body through the second semiconductor layer into the first semiconductor layer; a drain region arranged in the first semiconductor layer; and a plurality of transistor cells each coupled between the drain region and a source node. The trench structure subdivides the second semiconductor layer into a plurality of mesa regions and includes at least one cavity. At least one of the plurality of transistor cells is at least partially integrated in each of the mesa regions.

A wide gap semiconductor device has: a wide gap semiconductor layer; and a metal layer 20 provided on the wide gap semiconductor layer. The metal layer 20 has a single crystal layer 21 in an interface region at an interface with the wide gap semiconductor layer. When it is assumed that a lattice constant, in an equilibrium state, of a metal constituting the metal layer 20 is L, the single crystal layer 21 in the interface region includes a first region in which a lattice constant L1 is smaller than L by 1.5% to 8%.

Disclosed is a silicon carbide MOSFET device and a manufacturing method thereof. The manufacturing method comprises: forming a source region in an epitaxial layer; forming a body region in the epitaxial layer; forming a gate structure, comprising a gate dielectric layer, a gate conductor layer and an interlayer dielectric layer; forming an opening in the interlayer dielectric layer to expose the source region; forming a source contact connected to the source region via the opening, wherein an ion implantation angle of the ion implantation process is controlled to make a transverse extension range of the body region larger than a transverse extension range of the source region, so that a channel that extends transversely is formed by a portion, which is peripheral to the source region, of the body region, and at least a portion of the gate conductor layer is located above the channel.

A semiconductor device according to the present invention includes a first conductive-type SiC semiconductor layer, and a Schottky metal, comprising molybdenum and having a thickness of 10 nm to 150 nm, that contacts the surface of the SiC semiconductor layer. The junction of the SiC semiconductor layer to the Schottky metal has a planar structure, or a structure with recesses and protrusions of equal to or less than 5 nm. A method for manufacturing a semiconductor device according to the present invention includes: a step of forming a Schottky metal, comprising molybdenum and having a thickness of 10 nm to 150 nm, on the surface of a first conductive-type SiC semiconductor layer; and a step for heat treating the Schottky metal whilst the surface thereof is exposed, and structuring the junction of the SiC semiconductor layer to the Schottky metal to be planar, or to have recesses and protrusions of equal to or less than 5 nm.

Provided is a manufacturing method for manufacturing a SiC substrate having a flattened surface, including etching the surface of the SiC substrate by irradiating the surface of the SiC substrate with atomic hydrogen while the SiC substrate having an off angle is heated. In the etching, the SiC substrate may be heated within a range of 800° C. or higher and 1200° C. or lower.

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.

A field effect gas sensor, for detecting a presence of a gaseous substance in a gas mixture, the field effect gas sensor comprising: a SiC semiconductor structure; an electron insulating layer covering a first portion of the SiC semiconductor structure; a first contact structure at least partly separated from the SiC semiconductor structure by the electron insulating layer; and a second contact structure conductively connected to a second portion of the SiC semiconductor structure, wherein at least one of the electron insulating layer and the first contact structure is configured to interact with the gaseous substance to change an electrical property of the SiC semiconductor structure; and wherein the second contact structure comprises: an ohmic contact layer in direct contact with the second portion of the SiC semiconductor structure; and a barrier layer formed by an electrically conducting mid-transition-metal oxide covering the ohmic contact layer.

Disclosed is a bipolar semiconductor device, comprising a semiconductor body having a first surface; and a base region of a first doping type and a first emitter region in the semiconductor body, wherein the first emitter region adjoins the first surface and comprises a plurality of first type emitter regions of a second doping type complementary to the first doping type, a plurality of second type emitter regions of the second doping type, a plurality of third type emitter regions of the first doping type, and a recombination region comprising recombination centers, wherein the first type emitter regions and the second type emitter regions extend from the first surface into the semiconductor body, wherein the first type emitter regions have a higher doping concentration and extend deeper into the semiconductor body from the first surface than the second type emitter regions, wherein the third type emitter regions adjoin the first type emitter regions and the second type emitter regions, and wherein the recombination region is located at least in the first type emitter regions and the third type emitter regions.