A Schottky barrier diode includes a semiconductor layer including a Ga.sub.2O.sub.3-based single crystal, an anode electrode that forms a Schottky junction with the semiconductor layer and is configured so that a portion in contact with the semiconductor layer includes Mo or W, and a cathode electrode. A turn-on voltage thereof is not less than 0.3 V and not more than 0.5 V.

A Schottky barrier diode includes a semiconductor substrate made of gallium oxide, a drift layer made of gallium oxide and provided on the semiconductor substrate, an anode electrode brought into Schottky contact with the drift layer, and a cathode electrode brought into ohmic contact with the semiconductor substrate. The drift layer has a plurality of trenches formed in a position overlapping the anode electrode in a plan view. Among the plurality of trenches, a trench positioned at the end portion has a selectively increased width. Thus, the curvature radius of the bottom portion of the trench is increased, or an edge part constituted by the bottom portion as viewed in a cross section is divided into two parts. As a result, an electric field to be applied to the bottom portion of the trench positioned at the end portion is mitigated, making dielectric breakdown less likely to occur.

In a first aspect of a present inventive subject matter, a semiconductor device includes a crystalline oxide semiconductor layer; and at least one electrode electrically connected to the crystalline oxide semiconductor layer. The crystalline oxide semiconductor layer includes at least one trench in the crystalline oxide semiconductor layer at a side of a first surface of the crystalline oxide semiconductor layer. The trench includes a bottom, a side, and at least one arc portion with a radius of curvature that is in a range of 100 nm to 500 nm, and the at least one arc portion is positioned between the bottom and the side, and an angle between the side of the trench and the first surface of the crystalline oxide semiconductor layer is 90° or more.

A semiconductor device formed on a semiconductor substrate includes: an epitaxial layer overlaying the semiconductor substrate; a drain formed on back of the semiconductor substrate; a drain region that extends into the epitaxial layer; an active region comprising: a body disposed in the epitaxial layer; a source embedded in the body; a gate trench extending into the epitaxial layer; a gate disposed in the gate trench; an active region contact trench extending through the source and the body; and an active region contact electrode disposed within the active region contact trench; and an island region under the active region contact trench and disconnected from the body, the island region having an opposite polarity as the epitaxial layer; wherein the active region contact trench has a non-uniform depth.

A semiconductor device includes a semiconductor substrate, which includes an element region and an outer-periphery voltage withstanding region. The outer-periphery voltage withstanding region includes a plurality of p-type guard rings surrounding the element region in a multiple manner. Each of the guard rings includes a high concentration region and a low concentration region. A low concentration region of an outermost guard ring includes a first part positioned on an outer peripheral side of its high concentration region. Respective low concentration regions of the guard rings include respective second parts, each positioned in a range sandwiched between corresponding two adjacent high concentration regions among a plurality of concentration regions. A width of the first part on a front surface is wider than widths of the second parts on the front surface.

An object of the present invention is to provide a Schottky barrier diode less apt to cause dielectric breakdown due to concentration of an electric field. A Schottky barrier diode includes a semiconductor substrate 20 made of gallium oxide, a drift layer 30 made of gallium oxide and provided on the semiconductor substrate 20, an anode electrode 40 brought into Schottky contact with the drift layer 30, and a cathode electrode 50 brought into ohmic contact with the semiconductor substrate 20. The drift layer 30 has an outer peripheral trench 10 that surrounds the anode electrode 40 in a plan view, and the outer peripheral trench 10 is filled with a semiconductor material 11 having a conductivity type opposite to that of the drift layer 30. An electric field is dispersed by the presence of the thus configured outer peripheral trench 10. This alleviates electric field concentration on the corner of the anode electrode 40, making it less apt to cause dielectric breakdown.

A semiconductor device structure includes a region of semiconductor material having an active region and a termination region. An active structure is disposed in the active region and a termination structure is disposed in the termination region. In one embodiment, the termination structure includes a termination trench and a conductive structure within the termination trench and electrically isolated from the region of semiconductor material by a dielectric structure. A dielectric layer is disposed to overlap the termination trench to provide the termination structure as a floating structure. A Schottky contact region is disposed within the active region. A conductive layer is electrically connected to the Schottky contact region and the first conductive layer extends onto a surface of the dielectric layer and laterally overlaps at least a portion of the termination trench.

In a Schottky barrier diode region, a Schottky barrier diode is formed between an n-type drift layer and a metal layer, and in a body diode region, a p-type semiconductor region, a p-type semiconductor region, and a p-type semiconductor region are formed in order from a main surface side in the drift layer, and a body diode is formed between the p-type semiconductor region and the drift layer. An impurity concentration of the p-type semiconductor region is decreased lower than the impurity concentration of the p-type semiconductor regions, thereby increasing the reflux current flowing through the Schottky barrier diode and preventing the reflux current from flowing through the body diode.

The present embodiments relate to an apparatus and method of integrating a semiconductor cell in a non-active area of a MOSFET on a semiconductor substrate. An active area of the MOSFET may include a regular MOSFET cell. The semiconductor cell which can have various structures is configured to function as trench MOS barrier Schottky (TMBS) diode. Depending on its structure the TMBS diode may be integrated in a termination region or a shield tie region or a gate finger neighboring region in the non-active area. The integrated TMBS diode as such can limit the body diode conduction and improve the conduction and switching efficiency in a circuit. Additionally, an integrated TMBS diode may improve the softness of reverse recovery of the MOSFET, reduce drain to source voltage overshoot and ringing due to softer recovery and/or shield bounce without wasting any active area of the semiconductor die of the MOSFET.

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.