Abstract: In a vertical MOSFET having a trench gate structure, a lifetime killer region is provided in a p-type epitaxial layer formed by epitaxial growth. The lifetime killer region includes an electron lifetime killer that causes electrons entering the lifetime killer region to recombine and become extinct. As a result, the lifetime killer region decreases the electrons generated at the pn interface of the p-type epitaxial layer and an n-type drift layer and enables a configuration in which electrons are not delivered to the p-type epitaxial layer.

Abstract: A silicon carbide semiconductor device, including a silicon carbide substrate, a drift layer provided on a front surface of the silicon carbide substrate, an embedded layer selectively provided in a surface layer of the drift layer, an epitaxial layer provided on the drift layer, a channel layer provided on the epitaxial layer, a source region selectively provided in a surface layer of the channel layer, a trench penetrating the source region and the channel layer and reaching the epitaxial layer, a gate electrode provided in the trench via a gate insulating film, a source electrode in contact with the channel layer and the source region, and a drain electrode provided on a rear surface of the silicon carbide substrate. The embedded layer is arranged underneath the trench in a depth direction. A longitudinal direction of the trench, which is perpendicular to the depth direction, is parallel to the off-direction of the silicon carbide substrate.

Abstract: On a front surface of an n+-type starting substrate containing silicon carbide, a pin diode is configured having silicon carbide layers constituting an n+-type buffer layer, an n?-type drift layer, and a p+-type anode layer sequentially formed by epitaxial growth. The n+-type buffer layer is formed by so-called co-doping of nitrogen and vanadium, which forms a recombination center, together with an n-type impurity. The n+-type buffer layer includes a first part disposed at a side of a second interface of the buffer layer with the substrate and a second part disposed at side of a first interface of the buffer layer with the drift layer. The vanadium concentration in the second part is lower than that in the first part. The vanadium concentration in the second part is at most one tenth of the maximum value Vmax of the vanadium concentration in the n+-type buffer layer.

Abstract: A method for manufacturing an epitaxial wafer comprising a silicon carbide substrate and a silicon carbide voltage-blocking-layer, the method includes: epitaxially growing a buffer layer on the substrate, doping a main dopant for determining a conductivity type of the buffer layer and doping an auxiliary dopant for capturing minority carriers in the buffer layer at a doping concentration less than the doping concentration of the main dopant, so that the buffer layer enhances capturing and extinction of the minority carriers, the minority carriers flowing in a direction from the voltage-blocking-layer to the substrate, so that the buffer layer has a lower resistivity than the voltage-blocking-layer, and so that the buffer layer includes silicon carbide as a main component; and epitaxially growing the voltage-blocking-layer on the buffer layer.

Abstract: An n?-type epitaxial layer is grown on a front surface of the silicon carbide substrate by a CVD method in a mixed gas atmosphere containing a source gas, a carrier gas, a doping gas, an additive gas, and a gas containing vanadium. The doping gas is nitrogen gas; and the gas containing vanadium is vanadium tetrachloride gas. In the mixed gas atmosphere, the vanadium bonds with the nitrogen, producing vanadium nitride, whereby the nitrogen concentration in the mixed gas atmosphere substantially decreases. As a result, the nitrogen taken in by the n?-type epitaxial layer decreases and the n?-type epitaxial layer including nitrogen and vanadium as dopants is grown having a low impurity concentration.

Abstract: In a vertical MOSFET having a trench gate structure, a lifetime killer region is provided in a p-type epitaxial layer formed by epitaxial growth. The lifetime killer region includes an electron lifetime killer that causes electrons entering the lifetime killer region to recombine and become extinct. As a result, the lifetime killer region decreases the electrons generated at the pn interface of the p-type epitaxial layer and an n-type drift layer and enables a configuration in which electrons are not delivered to the p-type epitaxial layer.

Abstract: A silicon carbide semiconductor substrate, including a silicon carbide substrate of a first conductivity type, a buffer layer of the first conductivity type and an epitaxial layer of the first conductivity type. The silicon carbide substrate has a central part and a peripheral part surrounding the central part, and is doped with a first impurity that determines the first conductivity type. The buffer layer is provided on a front surface of the central part of the silicon carbide substrate, and is doped with the first impurity, of which a concentration is at least 1.0×1018/cm3, and a second impurity different from the first impurity. The epitaxial layer is provided on a front surface of the peripheral part of the silicon carbide substrate, and is doped with the first impurity, of which a concentration is lower than the concentration of the first impurity in the buffer layer.

Abstract: The SiC-IGBT includes a p-type collector layer, an n?-type voltage-blocking-layer provided on the collector layer, p-type base regions provided on the n?-type voltage-blocking-layer, n+-type emitter regions provided in an upper portion of the p-type base region, a gate insulating film provided in an upper portion of the voltage-blocking-layer, and a gate electrode provided on the gate insulating film. The p-type buffer layer has thickness of five micrometers or more and 20 micrometers or less and is doped with Al at impurity concentration of 5×1017 cm?3 or more and 5×1018 cm?3 or less and doped with B at impurity concentration of 2×1016 cm?3 or more and less than 5×1017 cm?3.

Abstract: On a first epitaxial layer of a first conductivity type or a second conductivity type provided on a front surface of a silicon carbide substrate, a mark indicating a crystal axis direction of the silicon carbide substrate within a margin of error of one degree is provided. The mark is created on the silicon carbide substrate by forming the first epitaxial layer of the first conductivity type or the second conductivity type on the front surface of the silicon carbide substrate, detecting a stacking fault from the first epitaxial layer, and confirming the crystal axis direction of the silicon carbide substrate from the detected stacking fault.

Abstract: A silicon carbide semiconductor device, including a silicon carbide substrate, a drift layer provided on a front surface of the silicon carbide substrate, an embedded layer selectively provided in a surface layer of the drift layer, an epitaxial layer provided on the drift layer, a channel layer provided on the epitaxial layer, a source region selectively provided in a surface layer of the channel layer, a trench penetrating the source region and the channel layer and reaching the epitaxial layer, a gate electrode provided in the trench via a gate insulating film, a source electrode in contact with the channel layer and the source region, and a drain electrode provided on a rear surface of the silicon carbide substrate. The embedded layer is arranged underneath the trench in a depth direction. A longitudinal direction of the trench, which is perpendicular to the depth direction, is parallel to the off-direction of the silicon carbide substrate.

Abstract: A silicon carbide semiconductor substrate includes a silicon carbide substrate of a first conductivity type, an epitaxial layer of the first conductivity type provided on a front surface of the silicon carbide substrate, an impurity concentration of the epitaxial layer being 1×1017/cm3 to 1×1018/cm3, and a film thickness of the epitaxial layer being 1 ?m to 5 ?m. The silicon carbide semiconductor substrate further includes a buffer layer of the first conductivity type provided on a surface of a first side of the epitaxial layer opposite a second side facing the silicon carbide substrate, an impurity concentration of the buffer layer being about a same as that of the silicon carbide substrate, and a drift layer of the first conductivity type provided on a surface of a first side of the buffer layer opposite a second side facing toward the silicon carbide substrate, an impurity concentration of the drift layer being lower than that of the buffer layer.

Abstract: On a first epitaxial layer of a first conductivity type or a second conductivity type provided on a front surface of a silicon carbide substrate, a mark indicating a crystal axis direction of the silicon carbide substrate within a margin of error of one degree is provided. The mark is created on the silicon carbide substrate by forming the first epitaxial layer of the first conductivity type or the second conductivity type on the front surface of the silicon carbide substrate, detecting a stacking fault from the first epitaxial layer, and confirming the crystal axis direction of the silicon carbide substrate from the detected stacking fault.

Abstract: A method for manufacturing an epitaxial wafer comprising a silicon carbide substrate and a silicon carbide voltage-blocking-layer, the method includes: epitaxially growing a buffer layer on the substrate, doping a main dopant for determining a conductivity type of the buffer layer and doping an auxiliary dopant for capturing minority carriers in the buffer layer at a doping concentration less than the doping concentration of the main dopant, so that the buffer layer enhances capturing and extinction of the minority carriers, the minority carriers flowing in a direction from the voltage-blocking-layer to the substrate, so that the buffer layer has a lower resistivity than the voltage-blocking-layer, and so that the buffer layer includes silicon carbide as a main component; and epitaxially growing the voltage-blocking-layer on the buffer layer.

Abstract: A silicon carbide semiconductor device, including a silicon carbide semiconductor substrate of a first conductivity type, a first silicon carbide semiconductor deposition layer of the first conductivity type, deposited on a front surface of the silicon carbide semiconductor substrate and having an impurity concentration that is lower than that of the silicon carbide semiconductor substrate, a base region of a second conductivity type, selectively provided in the first silicon carbide semiconductor deposition layer at a front surface thereof, and a second silicon carbide semiconductor deposition layer of the second conductivity type, deposited on the front surface of the first silicon carbide semiconductor deposition layer. The base region has an impurity concentration of 1×1018 to 1×1020/cm3 and a thickness of 0.3 to 1.0 ?m. The second silicon carbide semiconductor deposition layer has a surface defect density of 3 defects/cm2.

Abstract: A silicon carbide semiconductor element and a manufacturing method thereof are disclosed in which a low contact resistance is attained between an electrode film and a wiring conductor element, and the wiring conductor element is hardly detached from the electrode film. In the method, a nickel film and a nickel oxide film are laminated in this order on a surface of an n-type silicon carbide substrate or an n-type silicon carbide region of a silicon carbide substrate, followed by a heat treatment under a non-oxidizing condition. The heat treatment transforms a portion of the nickel film into a nickel silicide film. Then, the nickel oxide film is removed with hydrochloric acid solution, and subsequently, a nickel aluminum film and an aluminum film are laminated in this order on a surface of the nickel silicide film.

Abstract: Silicon carbide semiconductor device includes trench, in which connecting trench section is connected to straight trench section. Straight trench section includes first straight trench and second straight trench extending in parallel to each other. Connecting trench section includes first connecting trench perpendicular to straight trench section, second connecting trench that connects first straight trench and first connecting trench to each other, and third connecting trench that connects second straight trench and first connecting trench to each other. Second connecting trench extends at 30 degrees of angle with the extension of first straight trench. Third connecting trench extends at 30 degrees of angle with the extension of second straight trench. A manufacturing method according to the invention for manufacturing a silicon carbide semiconductor device facilitates preventing defects from being causes in a silicon carbide semiconductor device during the manufacture thereof.

Abstract: A SiC semiconductor substrate is disclosed which includes a SiC single crystal substrate, a nitrogen (N)-doped n-type SiC epitaxial layer in which nitrogen (N) is doped and a phosphorus (P)-doped n-type SiC epitaxial layer in which phosphorus (P) is doped. The nitrogen (N)-doped n-type SiC epitaxial layer and the phosphorus (P)-doped n-type SiC epitaxial layer are laminated on the silicon carbide single crystal substrate sequentially. The nitrogen (N)-doped n-type SiC epitaxial layer and the phosphorus (P)-doped n-type SiC epitaxial layer are formed by using two or more different dopants, for example, nitrogen and phosphorus, at the time of epitaxial growth. Basal plane dislocations in a SiC device can be reduced.

Abstract: Silicon carbide semiconductor device includes trench, in which connecting trench section is connected to straight trench section. Straight trench section includes first straight trench and second straight trench extending in parallel to each other. Connecting trench section includes first connecting trench perpendicular to straight trench section, second connecting trench that connects first straight trench and first connecting trench to each other, and third connecting trench that connects second straight trench and first connecting trench to each other. Second connecting trench extends at 30 degrees of angle with the extension of first straight trench. Third connecting trench extends at 30 degrees of angle with the extension of second straight trench. A manufacturing method according to the invention for manufacturing a silicon carbide semiconductor device facilitates preventing defects from being causes in a silicon carbide semiconductor device during the manufacture thereof.

Abstract: Silicon carbide semiconductor device includes trench, in which connecting trench section is connected to straight trench section. Straight trench section includes first straight trench and second straight trench extending in parallel to each other. Connecting trench section includes first connecting trench perpendicular to straight trench section, second connecting trench that connects first straight trench and first connecting trench to each other, and third connecting trench that connects second straight trench and first connecting trench to each other. Second connecting trench extends at 30 degrees of angle with the extension of first straight trench. Third connecting trench extends at 30 degrees of angle with the extension of second straight trench. A manufacturing method according to the invention for manufacturing a silicon carbide semiconductor device facilitates preventing defects from being causes in a silicon carbide semiconductor device during the manufacture thereof.

Abstract: A silicon carbide semiconductor element and a manufacturing method thereof are disclosed in which a low contact resistance is attained between an electrode film and a wiring conductor element, and the wiring conductor element is hardly detached from the electrode film. In the method, a nickel film and a nickel oxide film are laminated in this order on a surface of an n-type silicon carbide substrate or an n-type silicon carbide region of a silicon carbide substrate, followed by a heat treatment under a non-oxidizing condition. The heat treatment transforms a portion of the nickel film into a nickel silicide film. Then, the nickel oxide film is removed with hydrochloric acid solution, and subsequently, a nickel aluminum film and an aluminum film are laminated in this order on a surface of the nickel silicide film.