Tdk Corporation

Tamura Corporation

Novel Crystal Technology, Inc.

Jun Arima

Minoru Fujita

Jun Hirabayashi

Katsumi Kawasaki

Kohei Sasaki

Daisuke Inokuchi

Makio Kondo

Yutaka Matsuo

To prevent dielectric breakdown of a Schottky barrier diode using gallium oxide. A Schottky barrier diode has a drift layer provided on a semiconductor substrate, an anode electrode, and a cathode electrode. A part of the anode electrode is embedded in an outer peripheral trench and a center trench through an insulating film. The insulating film is formed such that the thickness thereof in the depth direction of the outer peripheral trench becomes larger toward the outside, whereby an outer peripheral wall Sof the anode electrode embedded in the outer peripheral trench is curved so as to approach vertical toward the outside. This results in relaxation of an electric field which occurs at the outer peripheral bottom portion of the outer peripheral trench upon application of a backward voltage.

Schottky barrier diode

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.

A crucible for growing a single-crystal in which a raw material melt for growing the single-crystal is solidified while being accommodated includes a side wall part configured to surround the raw material melt and a bottom part configured to support the raw material melt while being continuous with the side wall part, in which the side wall part has circumferential length redundancy inside the side wall part in a cross-sectional view. The side wall part has a portion where the circumference length is redundant inside any portion in the cross-sectional view, and when the crucible for growing a single-crystal is cooled in a cooling process after the single-crystal growth, the portion where the circumference length is redundant inside in the cross-sectional view is expanded to an outside of the crucible for growing a single-crystal.

Single-crystal growing crucible, single-crystal production method and single crystal

A Schottky barrier diodeincludes: 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.

In a crystal manufacturing method, first, a feedstock including a tapered tip portion is disposed above a crystal growth region. Then, a side surface of the tip portion is selectively heated and melted by radiant heat traveling diagonally upward while a shape of the tip portion is maintained, and the side surface of the tip portion is physically connected to an upper surface of the crystal growth region by a material melted from the side surface. In a crystal manufacturing apparatus, the radiant heat for melting the feedstock is radiated from an electric resistance heater.

Crystal manufacturing method, crystal manufacturing apparatus and single crystal

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 substratemade of gallium oxide, a drift layermade of gallium oxide and provided on the semiconductor substrate, an anode electrodebrought into Schottky contact with the drift layer, and a cathode electrodebrought into ohmic contact with the semiconductor substrate. The drift layerhas an outer peripheral trenchformed at a position surrounding the anode electrodein a plan view. An electric field is dispersed by the presence of the outer peripheral trenchformed in the drift layer. This alleviates concentration of the electric field on the corner of the anode electrode, making it unlikely 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.

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 electrodebrought 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 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.

A die for EFG-based single crystal growth includes a lower surface to be immersed into a raw material melt with an impurity added, a rectangular upper surface facing a seed crystal and having a long side and a short side, and a plurality of slit sections extending from the lower surface to the upper surface and causing the raw material melt to ascend from the lower surface to the upper surface. Respective longitudinal directions of openings of the plurality of slit sections on the upper surface are parallel to one another and non-parallel to the long side of the upper surface.

Die for EFG-based single crystal growth, EFG-based single crystal growth method, and EFG single crystal

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 substratemade of gallium oxide, a drift layermade of gallium oxide and provided on the semiconductor substrate, an anode electrodebrought into Schottky contact with the drift layer, and a cathode electrodebrought into ohmic contact with the semiconductor substrate. The drift layerhas an outer peripheral trenchthat surrounds the anode electrodein a plan view, and the outer peripheral trenchis filled with a semiconductor materialhaving a conductivity type opposite to that of the drift layer. An electric field is dispersed by the presence of the thus configured outer peripheral trench. This alleviates electric field concentration on the corner of the anode electrode, making it less apt to cause dielectric breakdown.

A trench MOS Schottky diode includes a first semiconductor layer including a GaO-based single crystal, a second semiconductor layer that is a layer stacked on the first semiconductor layer, includes a GaO-based single crystal, and includes a trench opened on a surface thereof opposite to the first semiconductor layer, an anode electrode formed on the surface of the second semiconductor layer, a cathode electrode formed on a surface of the first semiconductor layer, an insulating film covering the inner surface of the trench of the second semiconductor layer, and a trench electrode that is buried in the trench of the second semiconductor layer so as to be covered with the insulating film and is in contact with the anode electrode. The second semiconductor layer includes an insulating dry-etching-damaged layer with a thickness of not more than 0.8 &#x3bc;m in a region including the inner surface of the trench.

Trench MOS schottky diode and method for producing same

An object of the present invention is to provide a Schottky barrier diode using gallium oxide capable of suppressing heat generation and enhancing heat radiation performance while ensuring mechanical strength and handling performance. A Schottky barrier diode includes a semiconductor substratemade of gallium oxide having a recessed parton the second surface, an epitaxial layermade of gallium oxide and provided on a first surfaceof the semiconductor substrate; an anode electrodeprovided at a position overlapping the recessed partas viewed in the lamination direction and brought into Schottky contact with the epitaxial layer, and a cathode electrodeprovided in the recessed partof the semiconductor substrateand brought into ohmic contact with the semiconductor substrate. According to the present invention, since the thickness of the semiconductor substrate at a part thereof where forward current flows is selectively reduced, this makes it possible to suppress heat generation and to enhance heat radiation performance while ensuring mechanical strength and handling performance. Thus, even though gallium oxide having a low heat conductivity is used as the material of the semiconductor substrate, a temperature rise of the element can be suppressed.

Growing community of inventors

Tokyo, Japan

Jun Arima