Abstract: A silicon carbide semiconductor device that reduces an influence of an off-angle of a silicon carbide substrate on characteristics of the semiconductor device and achieves improved operational stability and reduced resistance. In a trench-gate silicon carbide MOSFET semiconductor device, a high-concentration well region is formed in a well region, and a distance from a first sidewall surface of a trench of the silicon carbide semiconductor to the high-concentration well region is smaller than a distance from a second sidewall surface of the trench to the high-concentration well region, the second sidewall surface facing the first sidewall surface of the trench through the gate electrode.

Abstract: It is expected that both reduction of the resistance of a source region and reduction of a leakage current in a gate oxide film be achieved in an MOSFET in a silicon carbide semiconductor device. A leakage current to occur in a gate oxide film of the MOSFET is suppressed by reducing roughness at an interface between a source region and the gate oxide film. If an impurity concentration is to become high at a surface portion of the source region, the gate oxide film is formed by dry oxidation or CVD process. If the gate oxide film is formed by wet oxidation, the impurity concentration at the surface portion of the source region is controlled at a low level.

Abstract: It is an object of the present invention to provide a silicon carbide semiconductor device that reduces an influence of an off-angle of a silicon carbide substrate on characteristics of the semiconductor device and achieves improved operational stability and reduced resistance. In a trench-gate silicon carbide MOSFET semiconductor device formed on the silicon carbide semiconductor substrate having the off-angle, a low-channel doped region is provided on a first sidewall surface side of the trench in a well region, and a high-channel doped region having an effective acceptor concentration lower than that of the low-channel doped region is provided on a second sidewall surface side of the trench in the well region.

Abstract: In a high speed switching power semiconductor device having a sense pad, a high voltage is generated during switching operations in well regions under the sense pad due to a displacement current flowing through its flow path with a resistance, whereby the power semiconductor device sometimes breaks down by dielectric breakdown of a thin insulating film such as a gate insulating film. In a power semiconductor device according to the invention, sense-pad well contact holes are provided on well regions positioned under the sense pad and penetrate a field insulating film thicker than the gate insulating film to connect to the source pad, thereby improving reliability.

Abstract: A device that increases a value of current flowing through a whole chip until a p-n diode in a unit cell close to a termination operates and reduces a size of the chip and a cost of the chip resulting from the reduced size. The device includes a second well region located to sandwich the entirety of a plurality of first well regions therein in plan view, a third separation region located to penetrate the second well region from a surface layer of the second well region in a depth direction, and a second Schottky electrode provided on the third separation region.

Abstract: A silicon carbide semiconductor device that reduces an influence of an off-angle of a silicon carbide substrate on characteristics of the semiconductor device and achieves improved operational stability and reduced resistance. In a trench-gate silicon carbide MOSFET semiconductor device, a high-concentration well region is formed in a well region, and a distance from a first sidewall surface of a trench of the silicon carbide semiconductor to the high-concentration well region is smaller than a distance from a second sidewall surface of the trench to the high-concentration well region, the second sidewall surface facing the first sidewall surface of the trench through the gate electrode.

Abstract: There is provided a trench-gate type semiconductor device that can prevent breakdown of a gate insulating film caused by a displacement current flowing into a protective diffusion layer at a portion of a trench underlying a gate electrode at a turn-off time and simultaneously improves a current density by narrowing a cell pitch. The semiconductor device has a gate electrode 7 embedded into a trench 5 penetrating a base region 3. The gate electrode 7 is disposed into a lattice shape in a planar view, and a protective diffusion layer 13 is formed in a drift layer 2a at the portion underlying thereof. At least one of blocks divided by the gate electrode 7 is a protective contact region 20 on which the trench 5 is entirely formed. A protective contact 21 for connecting the protective diffusion layer 13 at a bottom portion of the trench 5 and a source electrode 9 is disposed on the protective contact region 20.

Abstract: A semiconductor device capable of reducing ON-resistance changes with temperature, including a semiconductor substrate of a first conductivity type, a drift layer of the first conductivity type formed on the semiconductor substrate, a first well region of a second conductivity type formed in the front surface of the drift layer, a second well region of the second conductivity type formed in the front surface of the drift layer, and a gate structure that is formed on the front surface of the drift layer and forms a channel in the first well region and a channel in the second well region. A channel resistance of the channel formed in the first well region has a temperature characteristic that the channel resistance decreases with increasing temperature and a channel resistance of the channel formed in the second well region has a temperature characteristic that the channel resistance increases with increasing temperature.

Abstract: A trench-gate type semiconductor device that can prevent breakdown of a gate insulating film caused by a displacement current flowing into a protective diffusion layer at a portion of a trench underlying a gate electrode at a turn-off time and simultaneously improves a current density by narrowing a cell pitch. The semiconductor device includes a gate electrode embedded into a trench penetrating a base region. The gate electrode is disposed into a lattice shape in a planar view, and a protective diffusion layer is formed in a drift layer at the portion underlying thereof. At least one of blocks divided by the gate electrode is a protective contact region on which the trench is entirely formed. A protective contact for connecting the protective diffusion layer at a bottom portion of the trench and a source electrode is disposed on the protective contact region.

Abstract: In a semiconductor device having a built-in Schottky barrier diode as a reflux diode, a maximum unipolar current is increased in a reflux state and a leakage current is reduced in an OFF state. A Schottky electrode is provided in at least a part of a surface between adjacent well regions of a second conductivity type disposed on a surface layer side of a drift layer of a first conductivity type, and an impurity concentration of a first conductivity type in a first region provided in a lower part of the Schottky electrode and provided between the adjacent well regions is set to be higher than a first impurity concentration of a first conductivity type in the drift layer and to be lower than a second impurity concentration of a second conductivity type in the well region.

Abstract: An insulated gate silicon carbide semiconductor device includes: a drift layer of a first conductivity type on a silicon carbide substrate of 4H type with a {0001} plane having an off-angle of more than 0° as a main surface; a first base region; a source region; a trench; a gate insulating film; a protective diffusion layer; and a second base region. The trench sidewall surface in contact with the second base region is a surface having a trench off-angle of more than 0° in a <0001> direction with respect to a plane parallel to the <0001> direction. The insulated gate silicon carbide semiconductor device can relieve an electric field of a gate insulating film and suppress an increase in on-resistance and provide a method for manufacturing the same.

Abstract: It is an object of the present invention to provide a silicon carbide semiconductor device that reduces an influence of an off-angle of a silicon carbide substrate on characteristics of the semiconductor device and achieves improved operational stability and reduced resistance. In a trench-gate silicon carbide MOSFET semiconductor device formed on the silicon carbide semiconductor substrate having the off-angle, a low-channel doped region is provided on a first sidewall surface side of the trench in a well region, and a high-channel doped region having an effective acceptor concentration lower than that of the low-channel doped region is provided on a second sidewall surface side of the trench in the well region.

Abstract: A silicon carbide semiconductor device includes: a drift layer of the a first conduction type; a guard ring region of a second conduction type formed in annular form in a portion of one surface of the drift layer; a field insulating film formed on the one surface of the drift layer and surrounding the guard ring region; a Schottky electrode covering the guard ring region and the drift layer exposed inside the guard ring region and having an outer peripheral end existing on the field insulating film; and a surface electrode pad on the Schottky electrode, wherein an outer peripheral end of the surface electrode pad comes into contact with the field insulating film over the outer peripheral end of the Schottky electrode.

Abstract: A silicon-carbide semiconductor device that relaxes field intensity in a gate insulating film, and that has a low ON-resistance. The silicon-carbide semiconductor device includes: an n-type silicon-carbide substrate; a drift layer formed on a topside of the n-type silicon-carbide substrate; a trench formed in the drift layer and that includes therein a gate insulating film and a gate electrode; a p-type high-concentration well region formed parallel to the trench with a spacing therefrom and that has a depth larger than that of the trench; and a p-type body region formed to have a depth that gradually increases when nearing from a position upward from the bottom end of the trench by approximately the thickness of the gate insulating film at the bottom of the trench toward the lower end of the p-type high-concentration well region.

Abstract: In a semiconductor device having a built-in Schottky barrier diode as a reflux diode, a maximum unipolar current is increased in a reflux state and a leakage current is reduced in an OFF state. A Schottky electrode is provided in at least a part of a surface between adjacent well regions of a second conductivity type disposed on a surface layer side of a drift layer of a first conductivity type, and an impurity concentration of a first conductivity type in a first region provided in a lower part of the Schottky electrode and provided between the adjacent well regions is set to be higher than a first impurity concentration of a first conductivity type in the drift layer and to be lower than a second impurity concentration of a second conductivity type in the well region.

Abstract: A silicon carbide semiconductor device including an SBD measuring a temperature of a silicon carbide semiconductor element. The silicon carbide semiconductor device includes a MOSFET formed on a silicon carbide epitaxial substrate, and an SBD section measuring a temperature of the MOSFET. The SBD section includes an n-type cathode region in a surface portion of a silicon carbide drift layer; an anode titanium electrode formed on the cathode region, the electrode serving as a Schottky electrode; an n-type cathode contact region of a higher concentration than that of the cathode region, formed in the surface portion of the silicon carbide drift layer to make contact with the cathode region; a cathode ohmic electrode formed on the cathode contact region; and a first p-type well region formed within the silicon carbide drift layer to surround peripheries of the cathode region and the cathode contact region.

Abstract: A semiconductor device capable of suppressing time variation of a threshold voltage and a method of manufacturing the same. A semiconductor device according to the present invention comprises a drift layer formed on a semiconductor substrate, first well regions formed in a surface layer of the drift layer, being apart from one another, a gate insulating film formed, extending on the drift layer and each of the first well regions, a gate electrode selectively formed on the gate insulating film, a source contact hole penetrating through the gate insulating film and reaching the inside of each of the first well regions, and a residual compressive stress layer formed on at least a side surface of the source contact hole, in which a compressive stress remains.

Abstract: A source region of a MOSFET includes: a source contact region connected to a source pad; a source extension region adjacent to a channel region in a well region; and a source resistance control region arranged between the source extension region and the source contact region. The source resistance control region is different in an impurity concentration from the source extension region and the source contact region. These three regions are connected in series between the source pad and the channel region in the well region.

Abstract: A semiconductor device includes a semiconductor substrate of a first conductivity type, a drift layer of the first conductivity type which is formed on a first main surface of the semiconductor substrate, a second well region of a second conductivity type which is formed to surround a cell region of the drift layer, and a source pad for electrically connecting the second well regions and a source region of the cell region through a first well contact hole provided to penetrate a gate insulating film on the second well region, a second well contact hole provided to penetrate a field insulating film on the second well region and a source contact hole.

Abstract: A silicon carbide semiconductor device includes: a drift layer of the a first conduction type; a guard ring region of a second conduction type formed in annular form in a portion of one surface of the drift layer; a field insulating film formed on the one surface of the drift layer and surrounding the guard ring region; a Schottky electrode covering the guard ring region and the drift layer exposed inside the guard ring region and having an outer peripheral end existing on the field insulating film; and a surface electrode pad on the Schottky electrode, wherein an outer peripheral end of the surface electrode pad comes into contact with the field insulating film over the outer peripheral end of the Schottky electrode.