Abstract: A semiconductor device of the present invention includes a substrate having a drift layer, metal wiring formed on an upper surface of the substrate, and an electrode formed on a back surface of the substrate, wherein the lifetime of carriers in the drift layer satisfies the following expression 1: [Expression 1] ?>1.5×10?5exp (5.4×103tN-) ??expression 1 ?: the lifetime of carriers in the drift layer tN-: the layer thickness of the drift layer.

Abstract: The first layer is located on the first electrode and has the first conductivity type. The second layer is located on the first layer and has the second conductivity type. The third layer is located on the second layer. The second electrode is located on the third layer. The fourth layer is located between the second layer and the third layer, and has the second conductivity type. The third layer includes the first portion and the second portion. The first portion has the second conductivity type and has a peak value of an impurity concentration higher than the peak value of the impurity concentration in the second layer. The second portion has the first conductivity type. The area of the second portion accounts for not less than 20% and not more than 95% of the total area of the first portion and the second portion.

Abstract: An electric field buffer layer (13) is formed so as to surround an active region (12) from an outer peripheral portion of the active region (12) toward an outer peripheral portion of a semiconductor substrate (11). The electric field buffer layer (13) includes a plurality of P-type impurity layers (21 to 25). Each of the P-type impurity layers (21 to 25) includes P-type implantation layers (21a to 25a) and P-type diffusion layers (21b to 25b) that are formed so as to respectively surround the P-type implantation layers (21a to 25a) and contain P-type impurities at a concentration lower than that of the P-type implantation layers (21a to 25a). A first P-type implantation layer (21a) is formed to be in contact with or to partially overlap the active region (12). Each of the P-type diffusion layers (21b to 25b) is formed to have an expansion to a degree to which the first P-type diffusion layer (21b) is in contact with or overlaps a second P-type diffusion layer (22b).

Abstract: An insulated gate bipolar transistor having a gate electrode (7) and an emitter electrode (9) is provided in a transistor region. A termination region is arranged around the transistor region. A first N type buffer layer (18) is provided below an N type drift layer (1) in the transistor region. A P type collector layer (19) is provided below the first N type buffer layer (18). A second N type buffer layer (20) is provided below the N type drift layer (1) in the termination region. A collector electrode (21) is directly connected to the P type collector layer (19) and the second N type buffer layer (20). An impurity concentration of the second N type buffer layer (20) decreases as a distance from the collector electrode (21) decreases. The second N type buffer layer (20) does not form any ohmic contact with the collector electrode (21).

Abstract: A semiconductor device having first and second portions with opposite conductivity types. There are first through fourth layers in the semiconductor device. A peak value of the impurity concentration of the fourth layer is higher than the peak value of the impurity concentration of the second layer and lower than the peak value of the impurity concentration of a first portion of the third layer. The fourth layer includes a third portion located on the first portion and a fourth portion which is located on the second portion. The semiconductor device allows a decrease in the forward voltage drop and also allows an improvement of the safe operating area tolerance. Thus, it is possible to decrease the forward voltage drop, improve the maximum reverse voltage, and suppress oscillations at the time of recovery.

Abstract: A p-type anode layer (2) provided on an n-type drift layer (1) in the active region. A p-type diffusion layer (3) is provided on the n-type drift layer (1) in a termination region outside the active region. An oxide film (4) covers an outer periphery of the p-type anode layer (2). An anode electrode (5) is connected to a portion of the p-type anode layer (2) not covered with the oxide film (4). An n+-type cathode layer (7) is provided below the n-type drift layer (1). A cathode electrode (8) is connected to the n+-type cathode layer (7). An area of a portion of the p-type anode layer (2) covered with the oxide film (4) is 5 to 30% of a total area of the p-type anode layer (2).

Abstract: A semiconductor device includes a semiconductor substrate in which an active region and an edge termination region are defined, a semiconductor element formed in the active region, and first to fourth P layers formed in a region spanning from an edge portion of the active region to the edge termination region in the surface of the semiconductor substrate. The first to fourth P layers respectively have surface concentrations P(1) to P(4) that decrease in this order, bottom-end distances D(1) to D(4) that increase in this order, and distances B(1) to B(4) to the edge of the semiconductor substrate that increase in this order. The surface concentration P(4) is 10 to 1000 times the impurity concentration of the semiconductor substrate, and the bottom-end distance D(4) is in the range of 15 to 30 ?m.

Abstract: Valve device is provided with poppet valve for opening and closing flow path. Thread part is formed on shaft of this poppet valve, and driving gear is screwed into this thread part. Driving gear is rotated via pinion by motor, and thereby the poppet valve is moved to advance and retreat so as to control opening and closing of the flow path. Driving gear is provided so as to be able to advance and retreat in the axial direction of the pinion and the axial direction of the poppet valve while remaining engaged with pinion, and is normally held at a predetermined non-operating position by spring (biasing means). With this, even when the poppet valve is seated on the valve seat and has stopped moving, the driving gear moves, when further rotated, against the biasing force of spring from the non-operating position in the axial direction, and absorbs an impact that is applied to the driving means or the like. Damage of the driving means and the like due to the impact load can be prevented.

Abstract: The present invention provides a method for producing a hollow engine valve, with which the production process can be simplified and the processing precision can be improved. To this end, the present invention provides a method for producing a hollow engine valve (1) which is provided with a valve main body (10) in which a hollow hole (10c) is formed along a valve umbrella part (10a) and a hollow shaft part (10b), wherein a solid round bar (11) forming the material of the valve main body (10) is moulded to a semi-finished article (12) by means of a single hot-forging process, the semi-finished article (12) is subjected to rotary swaging whereby the semi-finished article (12) is moulded into a semi-finished article (13), the semi-finished article (13) is subjected to necking whereby the semi-finished article (13) is moulded into the valve main body (10) , and a shaft end sealing member (20) is joined to the end part of the hollow shaft part (10b) of the valve main body (10).

Abstract: A semiconductor device includes: an N-type drift layer; a P-type anode layer on the N-type drift layer; a trench penetrating the P-type anode layer; a conductive substance embedded in the trench via an insulating film; and an N-type buffer layer between the N-type drift layer and the P-type anode layer and having impurity concentration which is higher than that of the N-type drift layer.

Abstract: A semiconductor device includes a semiconductor substrate and a MOS transistor. The semiconductor substrate has the first main surface and the second main surface facing each other. The MOS transistor includes a gate electrode (5a) formed on the first main surface side, an emitter electrode (11) formed on the first main surface side, and a collector electrode (12) formed in contact with the second main surface. An element generates an electric field in a channel by a voltage applied to the gate electrode (5a), and controls the current between the emitter electrode (11) and the collector electrode (12) by the electric field in the channel. The spike density in the interface between the semiconductor substrate and the collector electrode (12) is not less than 0 and not more than 3×108 unit/cm2. Consequently, a semiconductor device suitable for parallel operation is provided.

Abstract: An insulated gate bipolar transistor having a gate electrode (7) and an emitter electrode (9) is provided in a transistor region. A termination region is arranged around the transistor region. A first N type buffer layer (18) is provided below an N type drift layer (1) in the transistor region. A P type collector layer (19) is provided below the first N type buffer layer (18). A second N type buffer layer (20) is provided below the N type drift layer (1) in the termination region. A collector electrode (21) is directly connected to the P type collector layer (19) and the second N type buffer layer (20). An impurity concentration of the second N type buffer layer (20) decreases as a distance from the collector electrode (21) decreases. The second N type buffer layer (20) does not form any ohmic contact with the collector electrode (21).

Abstract: A stabilizing plate portion is formed in a region of a first main surface lying between first and second insulated gate field effect transistor portions. The stabilizing plate portion includes a first stabilizing plate arranged closest to the first insulated gate field effect transistor portion and a second stabilizing plate arranged closest to the second insulated gate field effect transistor portion. An emitter electrode is electrically connected to an emitter region of each of the first and second insulated gate field effect transistor portions, electrically connected to each of the first and second stabilizing plates, and arranged on the entire first main surface lying between the first and second stabilizing plates, with an insulating layer being interposed.

Abstract: A semiconductor device includes a semiconductor substrate having a diode active region and an edge termination region adjacent to each other, a first region of a first conductivity type in the diode active region, a second region of a second conductivity type, a third region of the first conductivity type in the edge termination region, and a fourth region of the second conductivity type. The first region and the third region share a drift region of the first conductivity type. The first region and the third region share a fifth region of the first conductivity type. The drift region in the third region is greater in number of crystal defects per unit volume than the drift region in the first region in order that the drift region in the third region is shorter in carrier lifetime than the drift region in the first region.

Abstract: A semiconductor device includes: a transistor region including an IGBT having a gate electrode and an emitter electrode; a termination region placed around the transistor region; and an extraction region placed between the transistor and the termination region and extracting redundant carriers. A P-type layer is placed on an N-type drift layer in the extraction region. The P-type layer is connected to the emitter electrode. A dummy gate electrode is placed via an insulation film on the P-type layer. The dummy gate electrode is connected to the gate electrode. Life time of carriers in the termination region is shorter than life time of carriers in the transistor region and the extraction region.

Abstract: A semiconductor device includes a semiconductor substrate and a MOS transistor. The semiconductor substrate has the first main surface and the second main surface facing each other. The MOS transistor includes a gate electrode (5a) formed on the first main surface side, an emitter electrode (11) formed on the first main surface side, and a collector electrode (12) formed in contact with the second main surface. An element generates an electric field in a channel by a voltage applied to the gate electrode (5a), and controls the current between the emitter electrode (11) and the collector electrode (12) by the electric field in the channel. The spike density in the interface between the semiconductor substrate and the collector electrode (12) is not less than 0 and not more than 3×108 unit/cm2. Consequently, a semiconductor device suitable for parallel operation is provided.

Abstract: A semiconductor device includes a semiconductor substrate and a MOS transistor. The semiconductor substrate has the first main surface and the second main surface facing each other. The MOS transistor includes a gate electrode (5a) formed on the first main surface side, an emitter electrode (11) formed on the first main surface side, and a collector electrode (12) formed in contact with the second main surface. An element generates an electric field in a channel by a voltage applied to the gate electrode (5a), and controls the current between the emitter electrode (11) and the collector electrode (12) by the electric field in the channel. The spike density in the interface between the semiconductor substrate and the collector electrode (12) is not less than 0 and not more than 3×108 unit/cm2. Consequently, a semiconductor device suitable for parallel operation is provided.

Abstract: A valve assembly in which, even if a housing corrodes, application of a radially inward compression force to a heat-resistant filter can be suppressed. The valve assembly includes the housing having a gas path and a valve shaft hole, a valve having a valve shaft movably inserted in the valve shaft hole and also having a valve element connected to the valve shaft, and tubular heat-resistant filters installed between the inner peripheral surface of the valve shaft hole and the outer peripheral surface of the valve shaft and capturing dust in exhaust gas. The housing is made of cast iron. The valve assembly further has reinforcement collars installed between the inner peripheral surface of the valve shaft hole and the outer peripheral surfaces of the heat-resistant filters. The reinforcement collars have higher rigidity than the heat-resistant filters. At least the surfaces of the reinforcement collars are made of a high corrosion resistant material having higher corrosion resistance than the cast iron.

Abstract: A flow control valve in which corrosion is less likely to occur in the vicinity of a radial step portion in a gas passage of a housing and a method for manufacturing the same are provided. A flow control valve includes: a housing formed with a gas passage including a first cylinder member accommodating portion, a second cylinder member accommodating portion, and a radial step portion; a first cylinder member accommodated in the first cylinder member accommodating portion; a second cylinder member accommodated in the second cylinder member accommodating portion; and a valve body that is rotatably arranged inside the first cylinder member and the second cylinder member in the radial direction. The housing is formed of cast iron. At least surfaces of the first cylinder member and the second cylinder member are formed of a highly corrosion resistant material.

Abstract: A magnetic resonance imaging (MRI) system includes at least one controller configured to first acquire at least MRI locator image data for different portions of patient anatomy at each of different imaging stations for a defined multi-station locator sequence. An operator may interface with a respectively corresponding displayed locator image for each imaging station to set diagnostic scan sequence parameters for subsequent diagnostic MRI scans of corresponding portions of patient anatomy. Diagnostic MRI scan data is automatically acquired at each of the imaging stations in a multi-station diagnostic scan sequence that, if desired, can be seamlessly continued without operator interruption once begun.