A power semiconductor device includes a semiconductor layer structure comprising a drift region of a first conductivity type and a well region of a second conductivity type, a plurality of gate trenches including respective gate insulating layers and gate electrodes therein extending into the drift region, respective shielding patterns of the second conductivity type in respective portions of the drift region adjacent the gate trenches, and respective conduction enhancing regions of the first conductivity type in the respective portions of the drift region. The drift region comprises a first concentration of dopants of the first conductivity type, and the respective conduction enhancing regions comprise a second concentration of the dopants of the first conductivity type that is higher than the first concentration. Related devices and fabrication methods are also discussed.

Fabricating a vertical-channel junction field-effect transistor includes forming an unintentionally doped GaN layer on a bulk GaN layer by metalorganic chemical vapor deposition, forming a Cr/SiO.sub.2 hard mask on the unintentionally doped GaN layer, patterning a fin by electron beam lithography, defining the Cr and SiO.sub.2 hard masks by reactive ion etching, improving a regrowth surface with inductively coupled plasma etching, removing hard mask residuals, regrowing a p-GaN layer, selectively etching the p-GaN layer, forming gate electrodes by electron beam evaporation, and forming source and drain electrodes by electron beam evaporation. The resulting vertical-channel junction field-effect transistor includes a doped GaN layer, an unintentionally doped GaN layer on the doped GaN layer, and a p-GaN regrowth layer on the unintentionally doped GaN layer. Portions of the p-GaN regrowth layer are separated by a vertical channel of the unintentionally doped GaN layer.

A power semiconductor device includes a semiconductor layer structure comprising a drift region of a first conductivity type and a well region of a second conductivity type, a plurality of gate trenches including respective gate insulating layers and gate electrodes therein extending into the drift region, respective shielding patterns of the second conductivity type in respective portions of the drift region adjacent the gate trenches, and respective conduction enhancing regions of the first conductivity type in the respective portions of the drift region. The drift region comprises a first concentration of dopants of the first conductivity type, and the respective conduction enhancing regions comprise a second concentration of the dopants of the first conductivity type that is higher than the first concentration. Related devices and fabrication methods are also discussed.

A method for manufacturing a vertical JFET includes providing a III-nitride substrate having a first conductivity type and forming a first III-nitride layer coupled to the III-nitride substrate. The first III-nitride layer is characterized by a first dopant concentration and the first conductivity type. The method also includes forming a plurality of trenches within the first III-nitride layer and epitaxially regrowing a second III-nitride structure in the trenches. The second III-nitride structure is characterized by a second conductivity type. The method further includes forming a plurality of III-nitride fins, each coupled to the first III-nitride layer, wherein the plurality of III-nitride fins are separated by one of a plurality of recess regions, and epitaxially regrowing a III-nitride gate layer in the recess regions. The III-nitride gate layer is coupled to the second III-nitride structure and the III-nitride gate layer is characterized by the second conductivity type.

A method for manufacturing a vertical FET device includes providing a semiconductor substrate structure including a semiconductor substrate and a first semiconductor layer coupled to the semiconductor substrate. The first semiconductor layer is characterized by a first conductivity type. The method also includes forming a plurality of semiconductor fins coupled to the first semiconductor layer. Each of the plurality of semiconductor fins is separated by one of a plurality of recess regions. The method further includes epitaxially regrowing a semiconductor gate layer including a surface region in the plurality of recess regions. The method also includes forming an isolation region within the surface region of the semiconductor gate layer. The isolation region surrounds each of the plurality of semiconductor fins. The method includes forming a source contact structure coupled to each of the plurality of semiconductor fins and forming a gate contact structure coupled to the semiconductor gate layer.

An apparatus includes at least one vertical transistor, where the at least one vertical transistor includes: a substrate including a first semiconductor material, an array of three dimensional (3D) structures above the substrate, a sidewall heterojunction layer positioned on at least one vertical sidewall of each 3D structure, and an isolation region positioned between the 3D structures. Each 3D structure includes the first semiconductor material. The sidewall heterojunction layer includes a second semiconductor material, where the first and second semiconductor material have different bandgaps.

A silicon carbide substrate has a trench extending from a main surface of the silicon carbide substrate into the silicon carbide substrate. The trench has a trench width at a trench bottom. A shielding region is formed in the silicon carbide substrate. The shielding region extends along the trench bottom. In at least one doping plane extending approximately parallel to the trench bottom, a dopant concentration in the shielding region over a lateral first width deviates by not more than 10% from a maximum value of the dopant concentration. The first width is less than the trench width and is at least 30% of the trench width.

A method of forming an alignment contact includes: providing a III-nitride substrate; epitaxially growing a first III-nitride layer on the III-nitride substrate, wherein the first III-nitride layer is characterized by a first conductivity type; forming a plurality of III-nitride fins on the first III-nitride layer, wherein each the plurality of III-nitride fins is separated by one of a plurality of first recess regions, wherein the plurality of III-nitride fins are characterized by the first conductivity type; epitaxially regrowing a III-nitride source contact portion on each of the plurality of III-nitride fins; and forming a source contact structure on the III-nitride source contact portions.

A vertical junction field effect transistor (JFET) includes a substrate, an active region having a plurality of semiconductor fins, a source metal layer on an upper surface of the fins, a source metal pad layer coupled to the semiconductor fins through the source metal layer, a gate region surrounding the semiconductor fins, and a body diode surrounding the gate region

In one embodiment, an apparatus includes at least one vertical transistor, where the at least one vertical transistor includes: a substrate comprising a semiconductor material, an array of three dimensional (3D) structures above the substrate, a gate region, and an isolation region positioned between the 3D structures. Each 3D structure includes the semiconductor material. Each 3D structure also includes a first region having a first conductivity type and a second region having a second conductivity type, the second region including a portion of at least one vertical sidewall of the 3D structure. The gate region is present on a portion of an upper surface of the second region and the gate region is coupled to a portion of the at least one vertical sidewall of each 3D structure.