The semiconductor device of the present invention includes a first conductivity type semiconductor layer made of a wide bandgap semiconductor and a Schottky electrode formed to come into contact with a surface of the semiconductor layer, and has a threshold voltage V.sub.th of 0.3 V to 0.7 V and a leakage current J.sub.r of 110.sup.9 A/cm.sup.2 to 110.sup.4 A/cm.sup.2 in a rated voltage V.sub.R.

A semiconductor chip, which includes an n-type substrate, over which an n-type epitaxial layer having trenches introduced into the epitaxial layer and filled with p-type semiconductor is situated, the trenches each having a heavily doped p-type region on their upper side, the n.sup.+-type substrate being situated in such a manner, that an alternating sequence of n-type regions having a first width and p-type regions having a second width is present; a first metallic layer, which is provided on the front side of the semiconductor chip, forms an ohmic contact with the heavily doped p-type regions and is used as an anode electrode; a second metallic layer, which is provided on the back side of the semiconductor chip, constitutes an ohmic contact and is used as a cathode electrode; a dielectric layer provided, in each instance, between an n-type region and an adjacent p-type region, as well as p-type layers provided between the n-type regions and the first metallic layer.

A P-type Metal-Oxide-Semiconductor Field Effect Transistor (PMOSFET) includes a gate, a first source/drain region connected to the gate, and a second source/drain region on an opposite side of the gate than the first source/drain region. A first Schottky diode includes a first anode connected to the first source/drain region, and a first cathode connected to a body of the PMOSFET. A second Schottky diode includes a second anode connected to the second source/drain region, and a second cathode connected to the body of the PMOSFET.

A device that increases a value of current flowing through a whole chip until a p-n diode in a unit cell close to a termination operates and reduces a size of the chip and a cost of the chip resulting from the reduced size. The device includes a second well region located to sandwich the entirety of a plurality of first well regions therein in plan view, a third separation region located to penetrate the second well region from a surface layer of the second well region in a depth direction, and a second Schottky electrode provided on the third separation region.

A semiconductor device includes a semiconductor layer having a first surface and a second surface, a first electrode on the first surface, a second electrode on the second surface, a first semiconductor region of a first conductivity type in the semiconductor layer, a second semiconductor region of a second conductivity type in an element region of the semiconductor layer between the first semiconductor region and the first electrode, a third semiconductor region of the second conductivity type between the second semiconductor region and the first electrode, and a fourth semiconductor region of the second conductivity type in a termination region of the semiconductor layer inwardly of the first surface. A distance between the fourth semiconductor region and the second surface is greater than a distance between the second semiconductor region and the second surface.

A semiconductor device includes first and second second-conductivity-type region groups containing multiple second-conductivity-type regions that are disposed on a first silicon carbide semiconductor layer of a first conductivity type, arrayed in parallel following one direction with a space between each other, and first and second electrodes disposed on the first silicon carbide semiconductor layer and forming a Schottky junction with the first silicon carbide semiconductor layer. The first electrode covers a position where a distance from adjacent first and second second-conductivity-type regions included in a first second-conductivity-type region group, and a distance from a third second-conductivity-type region included in a second second-conductivity-type region group and adjacent to the first and second second-conductivity-type regions, are equal. A Schottky barrier between the first electrode and the first silicon carbide semiconductor layer is larger than a Schottky barrier between the second electrode and the first silicon carbide semiconductor layer.

A diode includes: a semiconductor substrate; a cathode metal layer contacting a bottom of the substrate; a semiconductor drift layer on the substrate; a graded aluminum gallium nitride (AlGaN) semiconductor barrier layer on the drift layer and having a larger bandgap than the drift layer, the barrier layer having a top surface and a bottom surface between the drift layer and the top surface, the barrier layer having an increasing aluminum composition from the bottom surface to the top surface; and an anode metal layer directly contacting the top surface of the barrier layer.

A semiconductor device has a drift region having an upper surface and a lower surface. A first contact is on the upper surface of the drift region and a second contact is on the lower surface of the drift region. The drift region includes a first semiconductor pillar that has a tapered sidewall and that is doped with first conductivity type impurities and a second semiconductor pillar on the tapered sidewall of the first semiconductor pillar, the second semiconductor pillar doped with second conductivity type impurities that have an opposite conductivity from the first conductivity type impurities.

A nitride semiconductor device includes: a nitride semiconductor layer; a gate electrode finger having at least one end portion, and extending along a surface of the nitride semiconductor layer; and a drain electrode finger having at least one end portion on the same side as that of the one end portion of the gate electrode finger, and extending along the gate electrode finger, wherein the one end portion of the drain electrode finger protrudes relative to the one end portion of the gate electrode finger.

A plurality of gate trenches is formed into an epitaxial region of a first conductivity type over a semiconductor substrate. One or more contact trenches are formed into the epitaxial region, each between two adjacent gate trenches. One or more source regions of the first conductivity type are formed in a top portion of the epitaxial region between a contact trench and a gate trench. A barrier metal is formed inside each contact trench.

Each gate trench is substantially filled with a conductive material separated from trench walls by a layer of dielectric material to form a gate . A heavily doped well region of a conductivity opposite the first type is provided in the epitaxial region proximate a bottom portion of each of the contact trenches. A horizontal width of a gap between the well region and the gate trench is about 0.05 nm to 0.2 nm.