A vertical semiconductor transistor is provided that includes: a source region, a drain region, and a body region formed in a semiconductor substrate; wherein the source region and the drain region are doped with a first type dopant; wherein the body region is doped with a second type dopant; and wherein the second type dopant has a doping profile within the body region that varies with distance from the source region.

A Field Effect Transistor (FET) may include a semiconductor substrate having a first conductivity type, a semiconductor layer of the first conductivity type formed over the substrate, and a pair of doped bodies of a second conductivity type opposite the first conductivity type formed in the semiconductor layer. A trench filled with a trench dielectric is formed within a region between the doped bodies. The FET may be a Vertical Metal-Oxide-Semiconductor FET (VMOSFET) including a gate dielectric disposed over the region between the doped bodies and the trench, and a gate electrode disposed over the gate dielectric, wherein the trench operates to prevent breakdown of the gate dielectric, or the FET may be a Junction FET. The FET may be designed to operate at radio frequencies or under heavy-ion bombardment. The semiconductor substrate and the semiconductor layer may comprise a wide band-gap semiconductor such as silicon carbide.

A Ga.sub.2O.sub.3-based semiconductor device includes a Ga.sub.2O.sub.3-based crystal layer including a donor, and an N-doped region formed in at least a part of the Ga.sub.2O.sub.3-based crystal layer.

A power semiconductor device includes a base semiconductor layer including impurities of a first conductivity type; a body portion provided on the base semiconductor layer and defined by a source trench, the body portion including a gate trench extending inwardly from an upper surface of the body portion; a gate electrode provided in the gate trench; a source electrode provided on the body portion and spaced apart from the gate electrode; and a drain electrode provided below the base semiconductor layer, wherein the body portion includes: a drift layer provided on the base semiconductor layer and including impurities of the first conductivity type; and a pair of shielding regions provided in the drift layer, spaced apart from each other in a horizontal direction, and spaced apart from the base semiconductor layer and the gate trench, the pair of shielding regions including impurities of a second conductivity type different from the first conductivity type.

A semiconductor device includes a semiconductor part, a first electrode at a back surface of the semiconductor part; a second electrode at a front surface of the semiconductor part; third and fourth electrodes provided between the semiconductor part and the second electrode. The third and fourth electrodes are arranged in a first direction along the front surface of the semiconductor part. The third electrode is electrically insulated from the semiconductor part by a first insulating film. The third electrode is electrically insulated from the second electrode by a second insulating film. The fourth electrode is electrically insulated from the semiconductor part by a third insulating film. The fourth electrode is electrically isolated from the third electrode. the third and fourth electrodes extend into the semiconductor part. The fourth electrode includes a material having a larger thermal conductivity than a thermal conductivity of a material of the third electrode.

A semiconductor device includes a semiconductor layer structure of a wide band-gap semiconductor material. The semiconductor layer structure includes a drift region having a first conductivity type and a well region having a second conductivity type. A plurality of segmented gate trenches extend in a first direction in the semiconductor layer structure. The segmented gate trenches include respective gate trench segments that are spaced apart from each other in the first direction with intervening regions of the semiconductor layer structure therebetween. Related devices and fabrication methods are also discussed.

A MOS transistor, in particular a vertical channel transistor, includes a semiconductor body housing a body region, a source region, a drain electrode and gate electrodes. The gate electrodes extend in corresponding recesses which are symmetrical with respect to an axis of symmetry of the semiconductor body. The transistor also has spacers which are also symmetrical with respect to the axis of symmetry. A source electrode extends in electrical contact with the source region at a surface portion of the semiconductor body surrounded by the spacers and is in particular adjacent to the spacers. During manufacture the spacers are used to form in an auto-aligning way the source electrode which is symmetrical with respect to the axis of symmetry and equidistant from the gate electrodes.

Semiconductor devices and methods of forming the devices are provided. Semiconductor devices include a semiconductor layer structure comprising a trench in an upper surface thereof, a dielectric layer in a lower portion of the trench, and a gate electrode in the trench and on the dielectric layer opposite the semiconductor layer structure. The trench may include rounded upper corner and a rounded lower corner. A center portion of a top surface of the dielectric layer may be curved, and the dielectric layer may be on opposed sidewalls of the trench. The dielectric layer may include a bottom dielectric layer on a bottom surface of the trench and on lower portions of the sidewalls of the trench and a gate dielectric layer on upper portions of the sidewalls of the trench and on the bottom dielectric layer.

A semiconductor device includes a semiconductor part; first and second electrodes respectively on back and front surfaces of the semiconductor part; a control electrode provided inside a trench of the semiconductor part; a third electrode provided inside the trench; a diode element provided at the front surface of the semiconductor part; a resistance element provided on the front surface of the semiconductor part via an insulating film, the diode element being electrically connected to the second electrode; a first interconnect electrically connecting the diode element and the resistance element, the first interconnect being electrically connected to the third electrode; and a second interconnect electrically connecting the resistance element and the semiconductor part. The resistance element is connected in series to the diode element. The diode element is provided to have a rectifying property reverse to a current direction flowing from the resistance element to the second electrode.

A MOSFET with saturation contact. The MOSFET with saturation contact includes an n-doped source region, a source contact, a contact structure, which extends from the source contact to the n-doped source region, and forms with the source contact a first conductive connection and forms with the n-doped source region a second conductive connection, a barrier layer and an insulating layer. The contact structure includes a section between the first conductive connection and the second conductive connection, which is embedded between the barrier layer and the dielectric layer and is configured in such a way that a two-dimensional electron gas is formed therein.