A Schottky barrier diode includes a semiconductor substrate made of gallium oxide, a drift layer made of gallium oxide and formed on the semiconductor substrate, an anode electrode brought into Schottky contact with the drift layer, a cathode electrode brought into ohmic contact with the semiconductor substrate, an insulating film covering the inner wall of a trench formed in the drift layer, and a protective film covering the anode electrode, wherein a part of the protective film is embedded in the trench. The part of the protective film is thus embedded in the trench, so that adhesion performance between the anode electrode and protective film is enhanced. This makes it possible to prevent peeling at the boundary between the anode electrode and the protective film.

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 brought into Schottky contact with the drift layer, and a cathode electrode brought into ohmic contact with the semiconductor substrate. The drift layer has an outer peripheral trench surrounding the anode electrode in a plan view. The surface of the drift layer positioned between the anode electrode and the outer peripheral trench is covered with a semiconductor layer having a conductivity type opposite to that of the drift layer.

Exemplary power semiconductor devices with features providing increased breakdown voltage and other benefits are disclosed.

A Schottky metal is in Schottky-contact with a center portion of a surface of an epitaxial layer. A peripheral trench is formed by digging from the surface of the epitaxial layer on a boundary portion between an active region where the Schottky metal is in Schottky-contact with the surface of the epitaxial layer and a peripheral region outside of the active region in a surface layer portion of the epitaxial layer. An insulating film is formed on an entire area of inner wall surfaces of the peripheral trench. There is provided with a conductor which is connected to the Schottky metal and is opposed to the entire area of the inner wall surfaces of the peripheral trench via the insulating film in the peripheral trench.

A semiconductor has a layer of a first conductivity type with a main surface, a trench separation structure which includes a separation trench formed in the main surface, a separation insulating film that covers a wall surface of the separation trench and a separation electrode that is embedded in the separation trench across the separation insulating film, the trench separation structure demarcating an outer region and an active region in the main surface, a floating region of a second conductivity type which is formed in an electrically floating state at a surface layer portion of the main surface along the trench separation structure in the outer region, and a Schottky electrode which is electrically connected to the separation electrode such as to retain the floating region in the electrically floating state in the outer region and which forms a Schottky junction with the main surface in the active region.

An object of the present invention is to provide a Schottky barrier diode which is less likely 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 formed at a position surrounding the anode electrode 40 in a plan view. An electric field is dispersed by the presence of the outer peripheral trench 10 formed in the drift layer 30. This alleviates concentration of the electric field on the corner of the anode electrode 40, making it unlikely to cause dielectric breakdown.

A manufacturing method of an electronic device includes: forming a drift layer of an N type; forming a trench in the drift layer; forming an edge-termination structure alongside the trench by implanting dopant species of a P type; and forming a depression region between the trench and the edge-termination structure by digging the drift layer. The steps of forming the depression region and the trench are carried out at the same time. The step of forming the depression region comprises patterning the drift layer to form a structural connection with the edge-termination structure having a first slope, and the step of forming the trench comprises etching the drift layer to define side walls of the trench, which have a second slope steeper than the first slope.

A method includes forming first and second trenches in a semiconductor substrate. The method further includes filling the first and second trenches with polysilicon. The polysilicon is oppositely doped from the semiconductor substrate. A Schottky contact is formed on the semiconductor substrate between the first and second trenches. The method also includes forming an anode for the Schottky contact. The anode is coupled to the polysilicon in the first and second trenches.

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.

Provided is a semiconductor device in which a leakage current is reduced, the semiconductor device which is particularly useful for power devices. A semiconductor device including at least: an n+-type semiconductor layer, which contains a crystalline oxide semiconductor as a major component; an n−-type semiconductor layer that is placed on the n+-type semiconductor layer, the n−-type semiconductor layer containing a crystalline oxide semiconductor as a major component; a high-resistance layer with at least a part thereof being embedded in the n−-type semiconductor layer, a depth d (μm) of the part embedded in the n−-type semiconductor layer satisfying d≥1.4; and a Schottky electrode that forms a Schottky junction with the n−-type semiconductor layer, the Schottky electrode having an edge located on the high-resistance layer.