A diode is formed by a polycrystalline silicon bar which includes a first doped region with a first conductivity type, a second doped region with a second conductivity type and an intrinsic region between the first and second doped regions. A conductive layer extends parallel to the polycrystalline silicon bar and separated from the polycrystalline silicon bar by a dielectric layer. The conductive layer is configured to be biased by a bias voltage.

A semiconductor device includes a junction field effect transistor (JFET) including a source electrode, a drain electrode, and a gate electrode, and a metal oxide semiconductor field effect transistor (MOSFET) including a source electrode, a drain electrode, and a gate electrode. The JFET and the MOSFET are cascode-connected such that the source electrode of the JFET and the drain electrode of the MOSFET are electrically connected. A gate voltage dependency of the JFET or a capacitance ratio of a mirror capacitance of the MOSFET to an input capacitance of the MOSFET is adjusted in a predetermined range.

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 includes a MOSFET including a drift layer, a channel layer, a trench gate structure, a source layer, a drain layer, a source electrode, and a drain electrode. The trench gate structure includes a trench penetrating the channel layer and protruding into the drift layer, a gate insulating film disposed on a wall surface of the trench, and a gate electrode disposed on the gate insulating film. A portion of the trench protruding into the drift layer is entirely covered with a well layer, and the well layer is connected to the channel layer.

A SiC epitaxial wafer includes a SiC substrate and an epitaxial layer laminated on the SiC substrate, wherein the epitaxial layer contains an impurity element which determines the conductivity type of the epitaxial layer and boron which has a conductivity type different from the conductivity type of the impurity element, and the concentration of boron in the center of the epitaxial layer is less than 5.0×10.sup.12 cm.sup.−3.

A semiconductor device includes an N+ type substrate, an N− type layer disposed on a first surface of the N+ type substrate and having a trench opened to a surface opposite to the surface facing the N+ type substrate, a P type region disposed in the N− type layer and disposed on a side surface of the trench, a gate electrode disposed in the trench, and a source electrode and a drain electrode insulated from the gate electrode. The N− type layer includes a P type shield region covering a bottom surface and an edge of the trench.

A semiconductor device includes: a substrate (10); a semiconductor layer (20) disposed on a main surface of this substrate (10); and a first main electrode (30) and a second main electrode (40), which are disposed on the substrate (10) separately from each other with the semiconductor layer (20) sandwiched therebetween and are individually end portions of a current path of a main current flowing in an on-state. The semiconductor layer (20) includes: a first conductivity-type drift region (21) through which a main current flows; a second conductivity-type column region (22) that is disposed inside the drift region (21) and extends in parallel to a current path; and an electric field relaxation region (23) that is disposed in at least a part between the drift region (21) and the column region (22) and is either a low-concentration region in which an impurity concentration is lower than in the same conductivity-type adjacent region or a non-doped region.

A method for manufacturing a semiconductor device includes implanting gas ions in a donor wafer and bonding the donor wafer to a carrier wafer to form a compound wafer. The method also includes subjecting the compound wafer to a thermal treatment to cause separation along a delamination layer and growing an epitaxial layer on a portion of separated compound wafer to form a semiconductor device layer. The method further includes cutting the carrier wafer.

A semiconductor device includes a switch element having a surface and first and second regions and including a first semiconductor material having a band-gap. The first region of the switch element is coupled to a source contact. A floating electrode has first and second ends. The first end of the floating electrode is coupled to the second region of the switch element. A voltage-support structure includes a second semiconductor material having a band-gap that is larger than the band-gap of the first semiconductor material. The voltage-support structure is in contact with the second end of the floating electrode. A drain contact is coupled to the voltage-support structure.