Abstract: An oil cooler includes flat tubes layered together with a clearance, wherein cooling water flows through the clearance. Each flat tube includes a first plate, a second plate, and a fin plate held between the first plate and the second plate. The first plate is recessed to form a fin plate accommodation portion accommodating the fin plate, wherein a thin portion is formed outside of the fin plate accommodation portion in a longitudinal direction of the flat tube. An oil port is provided at the thin portion. Each flat tube includes a guide wall at a lateral periphery thereof, wherein the guide wall faces the oil port in a width direction, and projects in a layering direction. The guide wall, the thin portion, and a lateral wall of the oil port form a nozzle portion to guide cooling water in the longitudinal direction.

Abstract: A heat exchanger for a vehicle is mounted in a vehicle having a power train through which an engine coolant, an engine oil and a transmission oil flow and in which a flow rate of the engine oil and a flow rate of the transmission oil are different from each other. A first flow passage for causing the engine coolant to flow, a second flow passage for causing the engine oil to flow, and a third flow passage for causing the transmission oil to flow are formed through lamination of a plurality of plates. The heat exchanger includes a region where the first flow passage is adjacent only to that one of the second flow passage and the third flow passage through which a fluid flows at lower flow rate.

Abstract: A heat exchanger for a vehicle is mounted in a vehicle having a power train through which an engine coolant, an engine oil and a transmission oil flow and in which a flow rate of the engine oil and a flow rate of the transmission oil are different from each other. A first flow passage for causing the engine coolant to flow, a second flow passage for causing the engine oil to flow, and a third flow passage for causing the transmission oil to flow are formed through lamination of a plurality of plates. The heat exchanger includes a region where the first flow passage is adjacent only to that one of the second flow passage and the third flow passage through which a fluid flows at lower flow rate.

Abstract: A method of manufacturing a silicon carbide substrate has the following steps. A silicon carbide source material is partially sublimated. After partially sublimating the silicon carbide source material, a seed substrate having a main surface is placed in a growth container. By sublimating the remainder of the silicon carbide source material in the growth container, a silicon carbide crystal grows on the main surface of the seed substrate. In this way, an increase of dislocations in the main surface of the seed substrate can be suppressed, thereby providing a method of manufacturing a silicon carbide substrate having few dislocations.

Abstract: A method of manufacturing a silicon carbide substrate has the following steps. A silicon carbide source material is partially sublimated. After partially sublimating the silicon carbide source material, a seed substrate having a main surface is placed in a growth container. By sublimating the remainder of the silicon carbide source material in the growth container, a silicon carbide crystal grows on the main surface of the seed substrate. In this way, an increase of dislocations in the main surface of the seed substrate can be suppressed, thereby providing a method of manufacturing a silicon carbide substrate having few dislocations.

Abstract: A method of manufacturing a silicon carbide substrate has the following steps. A silicon carbide source material is partially sublimated. After partially sublimating the silicon carbide source material, a seed substrate having a main surface is placed in a growth container. By sublimating the remainder of the silicon carbide source material in the growth container, a silicon carbide crystal grows on the main surface of the seed substrate. In this way, an increase of dislocations in the main surface of the seed substrate can be suppressed, thereby providing a method of manufacturing a silicon carbide substrate having few dislocations.

Abstract: A first impurity region is formed by ion implantation through a first opening formed in a mask layer. By depositing a spacer layer on an etching stop layer on which the mask layer has been provided, a mask portion having the mask layer and the spacer layer is formed. By anisotropically etching the spacer layer, a second opening surrounded by a second sidewall is formed in the mask portion. A second impurity region is formed by ion implantation through the second opening. An angle of the second sidewall with respect to a surface is 90°±10° across a height as great as a second depth. Thus, accuracy in extension of an impurity region can be enhanced.

Abstract: An oil cooler includes flat tubes layered together with a clearance, wherein cooling water flows through the clearance. Each flat tube includes a first plate, a second plate, and a fin plate held between the first plate and the second plate. The first plate is recessed to form a fin plate accommodation portion accommodating the fin plate, wherein a thin portion is formed outside of the fin plate accommodation portion in a longitudinal direction of the flat tube. An oil port is provided at the thin portion. Each flat tube includes a guide wall at a lateral periphery thereof, wherein the guide wall faces the oil port in a width direction, and projects in a layering direction. The guide wall, the thin portion, and a lateral wall of the oil port form a nozzle portion to guide cooling water in the longitudinal direction.

Abstract: A first impurity region is formed by ion implantation through a first opening formed in a mask layer. By depositing a spacer layer on an etching stop layer on which the mask layer has been provided, a mask portion having the mask layer and the spacer layer is formed. By anisotropically etching the spacer layer, a second opening surrounded by a second sidewall is formed in the mask portion. A second impurity region is formed by ion implantation through the second opening. An angle of the second sidewall with respect to a surface is 90°±10° across a height as great as a second depth. Thus, accuracy in extension of an impurity region can be enhanced.

Abstract: A first impurity region is formed by ion implantation through a first opening formed in a mask layer. By depositing a spacer layer on an etching stop layer on which the mask layer has been provided, a mask portion having the mask layer and the spacer layer is formed. By anisotropically etching the spacer layer, a second opening surrounded by a second sidewall is formed in the mask portion. A second impurity region is formed by ion implantation through the second opening. An angle of the second sidewall with respect to a surface is 90°±10° across a height as great as a second depth. Thus, accuracy in extension of an impurity region can be enhanced.

Abstract: A method for manufacturing a silicon carbide semiconductor device includes the step of forming a mask pattern of a silicon oxide film by removing a portion of the silicon oxide film by means of etching employing a gas containing oxygen gas and at least one fluorine compound gas selected from a group consisting of CF4, C2F6, C3F8, and SF6.

Abstract: A first impurity region is formed by ion implantation through a first opening formed in a mask layer. By depositing a spacer layer on an etching stop layer on which the mask layer has been provided, a mask portion having the mask layer and the spacer layer is formed. By anisotropically etching the spacer layer, a second opening surrounded by a second sidewall is formed in the mask portion. A second impurity region is formed by ion implantation through the second opening. An angle of the second sidewall with respect to a surface is 90°±10° across a height as great as a second depth. Thus, accuracy in extension of an impurity region can be enhanced.

Abstract: Provided is a method for manufacturing a silicon carbide crystal, including the steps of: placing a seed substrate and a source material for the silicon carbide crystal within a growth container; and growing the silicon carbide crystal with a diameter of more than 4 inches on a surface of the seed substrate by a sublimation method, in the step of growing, a pressure within the growth container being changed from a predetermined pressure, at a predetermined change rate.

Abstract: A silicon carbide substrate having a surface is prepared. A coating film made of a first material is formed directly on the surface of the silicon carbide substrate. A mask layer made of a second material is formed on the coating film. The first material is higher in adhesiveness with silicon carbide than the second material. A first opening is formed in the mask layer. First impurity ions for providing a first conductivity type are implanted into the silicon carbide substrate by using ion beams passing through the first opening in the mask layer and through the coating film.

Abstract: A method for manufacturing a silicon carbide semiconductor device includes the step of forming a mask pattern of a silicon oxide film by removing a portion of the silicon oxide film by means of etching employing a gas containing oxygen gas and at least one fluorine compound gas selected from a group consisting of CF4, C2F6, C3F8, and SF6.

Abstract: A first impurity region is formed by ion implantation through a first opening formed in a mask layer. By depositing a spacer layer on an etching stop layer on which the mask layer has been provided, a mask portion having the mask layer and the spacer layer is formed. By anisotropically etching the spacer layer, a second opening surrounded by a second sidewall is formed in the mask portion. A second impurity region is formed by ion implantation through the second opening. An angle of the second sidewall with respect to a surface is 90°±10° across a height as great as a second depth. Thus, accuracy in extension of an impurity region can be enhanced.