Silicon carbide (SiC) junction field effect transistors (JFETs) are presented herein. A deep implant (e.g., a deep p-type implant) forms a JFET gate (106). MET gate and MET source (108) may be implemented with heavily doped n-type (N+) and heavily doped p-type (P+) implants, respectively. Termination regions may be implemented by using equipotential rings formed by deep implants (e.g., deep p-type implants).

A semiconductor device contains a JFET with a channel layer having a first conductivity type in a substrate. The JFET has a back gate having a second, opposite, conductivity type below the channel. The back gate is laterally aligned with the channel layer. The semiconductor device is formed by forming a channel mask over the substrate of the semiconductor device which exposes an area for the channel dopants. The channel dopants are implanted into the substrate in the area exposed by the channel mask while the channel mask is in place. The back gate dopants are implanted into the substrate while the channel mask is in place, so that the implanted channel dopants are laterally aligned with the implanted channel dopants.

A Field Effect Transistor including: a channel with one end designated the source and the other end designated the drain; a means for connecting to said source end of said channel; a means for connecting to said drain end of said channel; a gate divided into a plurality of segments each insulated from one another; a means for adjusting the bias of each of said segments independently of one another, whereby the depletion region in said channel can be adjusted to avoid pinch-off and to maximize the efficiency of said Field Effect Transistor.

A cell structure for a field effect transistor having same gate and source doping includes: a silicon carbide substrate with a doping type of a first conductivity type; a semiconductor epitaxial layer of the first conductivity type and a first electrode respectively provided on front and back faces of the silicon carbide substrate; and a floating region of a second conductivity type, a gate implantation region of the first conductivity type, and a source implantation region of the first conductivity type sequentially provided on the semiconductor epitaxial layer of the first conductivity type, wherein a gate is provided on the gate implantation region, a source is provided on the source implantation region, an inter-electrode dielectric is provided between the gate implantation region and the source implantation region, and the inter-electrode dielectric is used for isolating the gate from the source.

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.

Junction field effect transistors (JFETs) and related manufacturing methods are disclosed herein. A disclosed JFET includes a vertical channel region located in a mesa and a first channel control region located on a first side of the mesa. The first channel control region is at least one of a gate region and a first base region. The JEFT also includes a second base region located on a second side of the mesa and extending through the mesa to contact the vertical channel region. The vertical channel can be an implanted vertical channel. The vertical channel can be asymmetrically located in the mesa towards the first side of the mesa.

A semiconductor device including a substrate, a plurality of III-nitride semiconductor layers, a source electrode, a gate electrode, a drain electrode, and a doped layer. The III-nitride semiconductor layers are disposed on the substrate. A two dimensional electron gas (2DEG) channel is formed in the III-nitride semiconductor layers. The source electrode, the gate electrode, and the drain electrode are disposed on the III-nitride semiconductor layers. The gate electrode is located between the source electrode and the drain electrode. The source electrode and the drain electrode are electrically connected to the 2DEG channel. A lateral direction is defined from the source electrode to the drain electrode. The doped layer is disposed between the gate electrode and the III-nitride semiconductor layers. The doped layer includes a plurality of dopants, and a concentration of the dopants varies along the lateral direction.

Provided is a semiconductor element in which a two-dimensional hole gas with an enough concentration can exist, even though the p-type GaN layer is not provided on the topmost surface of the polarization super junction region.

The semiconductor element comprises a polarization super junction region comprising an undoped GaN layer 11 with a thickness a [nm] (a is not smaller than 10 nm and not larger than 1000 nm), an Al.sub.xGa.sub.1-xN layer 12 and an undoped GaN layer 13. The Al composition x and the thickness t [nm] of the Al.sub.xGa.sub.1-xN layer 12 satisfy the following equation

t≧α(a)x.sup.β(a)

Where α is expressed as Log (α)=p.sub.0+p.sub.1 log (a)+p.sub.2{log (a)}.sup.2 (p.sub.0=7.3295, p.sub.1=−3.5599, p.sub.2=0.6912) and β is expressed as β=p′.sub.0+p′.sub.1 log (a)+p′.sub.2{log (a)}.sup.2 (p′.sub.0=−3.6509, p′.sub.1=1.9445, p′.sub.2=−0.3793).

Semiconductor devices are provided. A semiconductor device includes a first active pattern on a first region of a substrate, a pair of first source/drain patterns on the first active pattern, a first channel pattern between the pair of first source/drain patterns, and a gate electrode that extends across the first channel pattern. The gate electrode is on an uppermost surface and at least one sidewall of the first channel pattern. The gate electrode includes a first metal pattern including a p-type work function metal, a second metal pattern on the first metal pattern and including an n-type work function metal, a first barrier pattern on the second metal pattern and including an amorphous metal layer that includes tungsten (W), carbon (C), and nitrogen (N), and a second barrier pattern on the first barrier pattern. The second barrier pattern includes the p-type work function metal.

A semiconductor device includes: a substrate; a channel layer constituted of a single nitride semiconductor on the substrate; a first barrier layer which is a nitride semiconductor on a part of an upper surface of the channel layer and having a band gap larger than that of the channel layer; a gate layer which is a nitride semiconductor on and in contact with the first barrier layer; a second barrier layer which is a nitride semiconductor in contact with the first barrier layer in an area where the gate layer is not disposed above the channel layer, and having a band gap larger than that of the channel layer and having a thickness or a band gap independent from the first barrier layer; a gate electrode on the gate layer; and a source electrode and a drain electrode spaced apart from the gate layer and on the second barrier layer.