A Schottky barrier diode 1 includes: a semiconductor substrate made of gallium oxide; a drift layer made of gallium oxide; an anode electrode brought into Schottky contact with an upper surface of the drift layer; and a cathode electrode brought into ohmic contact with a lower surface of the semiconductor substrate. A ring-shaped outer peripheral trench is formed in the upper surface of the drift layer, and the anode electrode is partly filled in the outer peripheral trench. A ring-shaped back surface trench is formed in the lower surface of the semiconductor substrate such that the bottom thereof reaches the drift layer. This limits a current path to the area surrounded by the back surface trench, thereby mitigating electric field concentration in the vicinity of the bottom of the outer peripheral trench.

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 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.

A semiconductor device having a termination structure is provided that is useful for trench semiconductor devices, such as trench Schottky diodes. The device includes a termination structure having a primary termination trench including a first insulating layer arranged on a sidewall and bottom, and a first polysilicon region spaced apart from the sidewall and bottom by the first insulating layer; and a secondary termination trench arranged further away from the active region than the primary termination trench. The secondary termination trench includes a second insulating layer arranged on a sidewall and bottom, and polysilicon spacers separated from the sidewall and bottom by the second insulating layer. The polysilicon spacers are spaced apart and arranged on opposing ends of the secondary termination trench in an outward direction with respect to the active region, and a width of the primary termination trench is less than a width of the secondary termination trench.

A semiconductor Schottky rectifier built in an epitaxial semiconductor layer over a substrate has an anode structure and a cathode structure extending from the surface of the epitaxial layer. The cathode contact structure has a trench structure near the epi-layer and a vertical sidewall surface covered with a gate oxide layer. The cathode structure further comprises a polysilicon element adjacent to the gate oxide layer.

A semiconductor device structure comprises a region of semiconductor material comprising a first conductivity type, a first major surface, and a second major surface opposite to the first major surface. A first trench gate structure includes a first trench extending from the first major surface into the region of semiconductor material, a first dielectric structure is over sidewall surfaces and a portion of a lower surface of the first trench, wherein the first dielectric structure comprises a first opening adjacent to the lower surface of the first trench, a first recessed contact extends through the first opening, and a first contact region is over the first recessed contact within the first trench, wherein the first recessed contact and the first contact region comprise different materials. A first doped region comprising a second dopant conductivity type opposite to the first conductivity type is in the region of semiconductor material and is spaced apart from the first major surface and below the first trench. A gate contact region is in the region of semiconductor material and is electrically connected to the first doped region.

An object of the present invention is to provide a Schottky barrier diode less liable to cause dielectric breakdown due to concentration of an electric field. A Schottky barrier diode according to this disclosure includes a semiconductor substrate made of gallium oxide, a drift layer made of gallium oxide and provided on the semiconductor substrate, an anode electrode 40 brought into Schottky contact with the drift layer, a cathode electrode brought into ohmic contact with the semiconductor substrate, an insulating layer provided on the drift layer so as to surround the anode electrode in a plan view, and a semiconductor layer provided on a surface of a part of the drift layer that is positioned between the anode electrode and the insulating layer and on the insulating layer. The semiconductor layer has a conductivity type opposite to that of the drift layer.

An insulating film is formed on a front surface of a semiconductor layer in which a trench has been formed. An electric conductor is embedded into the trench, and the insulating film that has been formed on the semiconductor layer surface and that is adjacent to the trench is removed by etching so as to expose the semiconductor layer surface. The semiconductor layer surface is further etched such that the semiconductor layer surface is lowered relative to an upper end of the insulating film covering the inner surface of the trench. After that, a Schottky barrier junction is formed at the semiconductor layer surface.

A silicon substrate has first to fourth semiconductor regions. The third semiconductor region is separated from the first semiconductor region of a first conductivity type by the second semiconductor region of a second conductivity type. The fourth semiconductor region of the second conductivity type is separated from the second semiconductor region by the third semiconductor region. A first electrode is provided on a first surface. A barrier metal layer is provided on a first portion of a second surface. A second electrode is provided on the second surface, and is separated from the first portion of the second surface by the barrier metal layer. The second electrode includes an aluminum-silicon (Al—Si) layer in contact with a second portion of the second surface, and an Al layer separated from the second portion of the second surface by the Al—Si layer.

A Schottky diode includes a cathode terminal in a high voltage region of a semiconductor die, an anode terminal in a low voltage region of the semiconductor die, where the anode terminal and the cathode terminal are separated by a junction isolation termination situated between the high voltage region and the low voltage region. The Schottky diode includes a junction barrier Schottky diode or a trench metal-oxide-semiconductor (MOS) Schottky diode. The junction isolation termination includes pzener rings. The semiconductor die includes a substrate of a first conductivity type, an epitaxial layer of a second conductivity type situated on the substrate, a well region of the second conductivity type situated in the epitaxial layer in the high voltage region, and coupled to the cathode terminal, a Schottky barrier situated on the epitaxial layer in the low voltage region, and coupled to the anode terminal.