Abstract: In a method for producing an SiC semiconductor device, a p type layer is formed in a trench by epitaxially growing, and is then left only on a bottom portion and ends of the trench by hydrogen etching, thereby to form a p type SiC layer. Thus, the p type SiC layer can be formed without depending on diagonal ion implantation. Since it is not necessary to separately perform the diagonal ion implantation, it is less likely that a production process will be complicated due to transferring into an ion implantation apparatus, and thus manufacturing costs reduce. Since there is no damage due to a defect caused by the ion implantation, it is possible to reduce a drain leakage and to reliably restrict the p type SiC layer from remaining on the side surface of the trench.

Abstract: A silicon carbide semiconductor device includes: a vertical MOSFET having: a semiconductor substrate including a high-concentration impurity layer and a drift layer; a base region; a source region; a trench gate structure; a source electrode; and a drain electrode. The base region has a high-concentration base region and a low-concentration base region having a second conductivity type with an impurity concentration lower than the high-concentration base region, which are stacked each other. Each of the high-concentration base region and the low-concentration base region contacts a side surface of the trench.

Abstract: In a semiconductor substrate preparation step, a semiconductor substrate which is made of SiC and in which a first semiconductor region of a first conductivity type is formed is prepared. In a second semiconductor region forming step, a second semiconductor region is formed by implanting an impurity of a second conductivity type into a first semiconductor region through multiple ion implantation steps while varying implantation depths of the respective multiple ion implantation steps. In the second semiconductor region forming step, a dose amount of the impurity when an implantation energy of multiple ion implantation steps is the largest is smaller than a dose amount of impurity when the implantation energy is not the largest.

Abstract: A semiconductor device has a semiconductor substrate including a body region, a drift region, a trench that extends from a surface of the semiconductor substrate into the drift region through the body region, and a source region located adjacent to the trench in a range exposed to the surface of the semiconductor substrate, the source region being isolated from the drift region by the body region. A specific layer is disposed on a bottom of the trench, and it has a characteristic of forming a depletion layer at a junction between the specific layer and the drift region. An insulating layer covers an upper surface of the specific layer and a sidewall of the trench. A conductive portion is formed on a part of the side wall of the trench. The conductive portion is joined to the specific layer, and reaches the surface of the semiconductor substrate.

Abstract: A semiconductor substrate of a semiconductor device includes a first conductive body region that is formed in the element region; a second conductive drift region that is formed in the element region; a gate electrode that is formed in the element region, that is arranged in a gate trench, and that faces the body region; an insulating body that is formed in the element region and is arranged between the gate electrode and an inside wall of the gate trench; a first conductive floating region that is formed in the element region and that is surrounded by the drift region; a first voltage-resistance retaining structure that is formed in the peripheral region and that surrounds the element region; and a gate pad that is formed in the peripheral region, and is electrically connected to the gate electrode in a position on the element region-side of the first voltage-resistance retaining structure.

Abstract: A semiconductor device is provided with: a first conductivity type contact region; a second conductivity type body region; a first conductivity type drift region of; a trench formed through the contact region and body region from a front surface of the semiconductor substrate, wherein a bottom of the trench is positioned in the drift region; an insulating film covering an inner surface of the trench; a gate electrode accommodated in the trench in a state covered with the insulating film; and a second conductivity type floating region formed at a position deeper than the bottom of the trench, and adjacent to the bottom of the trench. The floating region includes a first layer adjacent to the bottom of the trench and a second layer formed at a position deeper than the first layer, wherein a width of the first layer is broader than a width of the second layer.

Abstract: A wafer examination device includes a probe, a fusion section and a measurement section. The probe is made of a metal which reacts with silicon carbide to produce silicide. The fusion section fuses the probe to a silicon carbide wafer as an examined object. The measurement section measures an electrical property of the silicon carbide wafer through the fused probe.

Abstract: A semiconductor device has a stacked structure in which a p-GaN layer, an SI-GaN layer, and an AlGaN layer are stacked, and has a gate electrode that is formed at a top surface side of the AlGaN layer. A band gap of the AlGaN layer is wider than a band gap of the p-GaN layer and the SI-GaN layer. Moreover, impurity concentration of the SI-GaN layer is less than 1×1017 cm?3. Semiconductor devices including III-V semiconductors may have a stable normally-off operation.

Abstract: A method for producing a semiconductor device includes: an arranging process of arranging a plurality of silicon carbide wafers having opposed first and surfaces so that the first surface and the second surface of adjacent silicon carbide wafers face each other and are separated in parallel; and a heat treatment process of heating the arranged plurality of silicon carbide wafers so that the first surface of each silicon carbide wafer becomes higher in temperature than the second surface thereof, and, in the adjacent silicon carbide wafers, the second surface of one silicon carbide wafer becomes higher in temperature than the first surface of the other silicon carbide wafer that faces the second surface.

Abstract: In a silicon carbide semiconductor device, a plurality of trenches has a longitudinal direction in one direction and is arranged in a stripe pattern. Each of the trenches has first and second sidewalls extending in the longitudinal direction. The first sidewall is at a first acute angle to one of a (11-20) plane and a (1-100) plane, the second sidewall is at a second acute angle to the one of the (11-20) plane and the (1-100) plane, and the first acute angle is smaller than the second acute angle. A first conductivity type region is in contact with only the first sidewall in the first and second sidewalls of each of the trenches, and a current path is formed on only the first sidewall in the first and second sidewalls.

Abstract: In a method of manufacturing a silicon carbide semiconductor device including a vertical switching element having a trench gate structure, with the use of a substrate having an off angle with respect to a (0001) plane or a (000-1) plane, a trench is formed from a surface of a source region to a depth reaching a drift layer through a base region so that a side wall surface of the trench faces a (11-20) plane or a (1-100) plane, and a gate oxide film is formed without performing sacrificial oxidation after formation of the trench.

Abstract: A manufacturing method of a semiconductor device includes: forming an electric metal layer by depositing metal as art electrode material on an inside of an opening of an insulating layer on a surface of an SiC semiconductor substrate; widening a gap between an inner wall surface in an opening formed in the insulating layer and the electrode metal layer by etching the insulating layer after the electrode metal layer is formed; and forming an ohmic contact between the electrode metal layer and the SiC semiconductor substrate by heating the SiC semiconductor substrate and the metal electrode layer after the insulating layer is etched.

Abstract: In a method for producing an SiC semiconductor device, a p type layer is formed in a trench by epitaxially growing, and is then left only on a bottom portion and ends of the trench by hydrogen etching, thereby to form a p type SiC layer. Thus, the p type SiC layer can be formed without depending on diagonal ion implantation. Since it is not necessary to separately perform the diagonal ion implantation, it is less likely that a production process will be complicated due to transferring into an ion implantation apparatus, and thus manufacturing costs reduce. Since there is no damage due to a defect caused by the ion implantation, it is possible to reduce a drain leakage and to reliably restrict the p type SiC layer from remaining on the side surface of the trench.

Abstract: An SiC semiconductor device has a p type region including a low concentration region and a high concentration region filled in a trench formed in a cell region. A p type column is provided by the low concentration region, and a p+ type deep layer is provided by the high concentration region. Thus, since a SJ structure can be made by the p type column and the n type column provided by the n type drift layer, an on-state resistance can be reduced. As a drain potential can be blocked by the p+ type deep layer, at turnoff, an electric field applied to the gate insulation film can be alleviated and thus breakage of the gate insulation film can be restricted. Therefore, the SiC semiconductor device can realize the reduction of the on-state resistance and the restriction of breakage of the gate insulation film.

Abstract: A manufacturing method of a silicon carbide semiconductor device includes: forming a drift layer on a silicon carbide substrate; forming a base layer on or in a surface portion of the drift layer; forming a source region in a surface portion of the base layer; forming a trench to penetrate the base layer and to reach the drift layer; forming a gate electrode on a gate insulation film in the trench; forming a source electrode electrically connected to the source region and the base layer; and forming a drain electrode on a back surface of the substrate. The forming of the trench includes: flattening a substrate surface; and etching to form the trench after flattening.

Abstract: In a silicon carbide semiconductor device, a p-type SiC layer is disposed in a corner of a bottom of a trench. Thus, even if an electric field is applied between a drain and a gate when a MOSFET is turned off, a depletion layer in a pn junction between the p-type SiC layer and an n? type drift layer greatly extends toward the n? type drift layer, and a high voltage caused by an influence of a drain voltage hardly enters a gate insulating film. Hence, an electric field concentration within the gate insulating film can be reduced, and the gate insulating film can be restricted from being broken. In this case, although the p-type SiC layer may be in a floating state, the p-type SiC layer is formed in only the corner of the bottom of the trench. Thus, the deterioration of the switching characteristic is relatively low.

Abstract: In a semiconductor substrate preparation step, a semiconductor substrate which is made of SiC and in which a first semiconductor region of a first conductivity type is formed is prepared. In a second semiconductor region forming step, a second semiconductor region is formed by implanting an impurity of a second conductivity type into a first semiconductor region through multiple ion implantation steps while varying implantation depths of the respective multiple ion implantation steps. In the second semiconductor region forming step, a dose amount of the impurity when an implantation energy of multiple ion implantation steps is the largest is smaller than a dose amount of impurity when the implantation energy is not the largest.

Abstract: A semiconductor substrate of a semiconductor device includes a body region of a first conductivity type, a drift region of a second conductivity type coming into contact with a lower surface of the body region, a gate electrode that is provided in a gate trench passing through the body region and extending to the drift region and faces the body region, and a gate insulator that is provided between the gate electrode and a wall surface of the gate trench. An inverted U-shaped section is formed in a lower surface of the gate insulator, and a floating region of the first conductivity type is formed in the inverted U-shaped section. The floating region protrudes under a portion that is located at a lowermost portion in the lower surface of the gate insulator.

Abstract: A semiconductor device has a semiconductor substrate including a body region, a drift region, a trench that extends from a surface of the semiconductor substrate into the drift region through the body region, and a source region located adjacent to the trench in a range exposed to the surface of the semiconductor substrate, the source region being isolated from the drift region by the body region. A specific layer is disposed on a bottom of the trench, and it has a characteristic of forming a depletion layer at a junction between the specific layer and the drift region. An insulating layer covers an upper surface of the specific layer and a sidewall of the trench. A conductive portion is formed on a part of the side wall of the trench. The conductive portion is joined to the specific layer, and reaches the surface of the semiconductor substrate.

Abstract: A semiconductor device includes: a semiconductor substrate that has an element region and a peripheral region that surrounds the element region; and a gate pad that is disposed in an area that is on a surface side of the semiconductor substrate. The element region is formed with an insulated gate semiconductor element that has a gate electrode. The peripheral region is formed with a first withstand voltage retaining structure that surrounds the element region and a second withstand voltage retaining structure that is located in a position on the first withstand voltage retaining structure side from an outer edge of the element region and on the element region side from a boundary of the first withstand voltage retaining structure on the element region side. The gate pad is electrically connected to the gate electrode and is disposed in an area in which the second withstand voltage retaining structure is formed.