Patents by Inventor Yasuo Kitou
Yasuo Kitou has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 10253431Abstract: A silicon carbide single crystal includes a spiral dislocation. The spiral dislocation includes a L dislocation having a burgers vector defined as b, which satisfies an equation of b><0001>+1/3<11-20>. The L dislocation has a density equal to or lower than 300 dislocations/cm2, preferably, 100 dislocations/cm2, since the L dislocation has large distortion and causes generation of leakage current. Thus, the silicon carbide single crystal with high quality is suitable for a device production which can suppress the leakage current.Type: GrantFiled: January 13, 2014Date of Patent: April 9, 2019Assignee: DENSO CORPORATIONInventors: Hiroyuki Kondo, Shoichi Onda, Yasuo Kitou, Hiroki Watanabe
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Publication number: 20150361586Abstract: A silicon carbide single crystal includes a spiral dislocation. The spiral dislocation includes a L dislocation having a burgers vector defined as b, which satisfies an equation of b><0001>+1/3<11-20>. The L dislocation has a density equal to or lower than 300 dislocations/cm2, preferably, 100 dislocations/cm2, since the L dislocation has large distortion and causes generation of leakage current. Thus, the silicon carbide single crystal with high quality is suitable for a device production which can suppress the leakage current.Type: ApplicationFiled: January 13, 2014Publication date: December 17, 2015Inventors: Hiroyuki KONDO, Shoichi ONDA, Yasuo KITOU, Hiroki WATANABE
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Patent number: 8980003Abstract: In a method of manufacturing a silicon carbide single crystal, a silicon carbide substrate having a surface of one of a (11-2n) plane and a (1-10n) plane, where n is any integer number greater than or equal to 0, is prepared. An epitaxial layer having a predetermined impurity concentration is grown on the one of the (11-2n) plane and the (1-10n) plane of the silicon carbide substrate by a chemical vapor deposition method so that a threading dislocation is discharged from a side surface of the epitaxial layer. A silicon carbide single crystal is grown into a bulk shape by a sublimation method on the one of the (11-2n) plane and the (1-10n) plane of the epitaxial layer from which the threading dislocation is discharged.Type: GrantFiled: February 9, 2010Date of Patent: March 17, 2015Assignee: DENSO CORPORATIONInventors: Hiroki Watanabe, Yasuo Kitou, Masami Naito
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Publication number: 20140127071Abstract: In a manufacturing method of a magnetic refrigeration material, a powder material made of La (Fe, Si)13 is molded by applying a pressure equal to or higher than 286 MPa and heating at a temperature equal to or lower than 600 degrees Celsius. Thus, a molded product of the magnetic refrigeration material is produced.Type: ApplicationFiled: November 5, 2013Publication date: May 8, 2014Applicant: DENSO CORPORATIONInventors: Tomonori Fujinaka, Yasuo Kitou
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Patent number: 8591654Abstract: A device for manufacturing a SiC single crystal includes: a raw material gas introduction pipe; a raw material gas heat chamber having a raw material gas supply passage for heating the gas in the passage; a reaction chamber having a second sidewall, an inner surface of which contacts an outer surface of a first sidewall of the heat chamber, and having a bottom, on which a SiC single crystal substrate is arranged; and a discharge pipe in a hollow center of the raw material gas heat chamber. The supply passage is disposed between an outer surface of the discharge pipe and an inner surface of the first sidewall. The discharge pipe discharges a residual gas, which is not used for crystal growth of the SiC single crystal.Type: GrantFiled: October 28, 2008Date of Patent: November 26, 2013Assignee: DENSO CORPORATIONInventors: Yasuo Kitou, Jun Kojima
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Patent number: 8518809Abstract: A manufacturing method of an SiC single crystal includes preparing an SiC substrate, implanting ions into a surface portion of the SiC substrate to form an ion implantation layer, activating the ions implanted into the surface portion of the SiC substrate by annealing, chemically etching the surface portion of the SiC substrate to form an etch pit that is caused by a threading screw dislocation included in the SiC substrate and performing an epitaxial growth of SiC to form an SiC growth layer on a surface of the SiC substrate including an inner wall of the etch pit in such a manner that portions of the SiC growth layer grown on the inner wall of the etch pit join with each other.Type: GrantFiled: December 1, 2011Date of Patent: August 27, 2013Assignee: DENSO CORPORATIONInventors: Hiroki Watanabe, Yasuo Kitou, Yasushi Furukawa, Kensaku Yamamoto, Hidefumi Takaya, Masahiro Sugimoto, Yukihiko Watanabe, Narumasa Soejima, Tsuyoshi Ishikawa
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Patent number: 8470091Abstract: A direction of a dislocation line of a threading dislocation is aligned, and an angle between the direction of the dislocation line of the threading dislocation and a [0001]-orientation c-axis is equal to or smaller than 22.5 degrees. The threading dislocation having the dislocation line along with the [0001]-orientation c-axis is perpendicular to a direction of a dislocation line of a basal plane dislocation. Accordingly, the dislocation does not provide an extended dislocation on the c-face, so that a stacking fault is not generated. Thus, when an electric device is formed in a SiC single crystal substrate having the direction of the dislocation line of the threading dislocation, which is the [0001]-orientation c-axis, a SiC semiconductor device is obtained such that device characteristics are excellent without deterioration, and a manufacturing yield ration is improved.Type: GrantFiled: January 21, 2010Date of Patent: June 25, 2013Assignee: DENSO CORPORATIONInventors: Yasuo Kitou, Hiroki Watanabe, Masanori Nagaya, Kensaku Yamamoto, Eiichi Okuno
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Publication number: 20120142173Abstract: A manufacturing method of an SiC single crystal includes preparing an SiC substrate, implanting ions into a surface portion of the SiC substrate to form an ion implantation layer, activating the ions implanted into the surface portion of the SiC substrate by annealing, chemically etching the surface portion of the SiC substrate to form an etch pit that is caused by a threading screw dislocation included in the SiC substrate and performing an epitaxial growth of SiC to form an SiC growth layer on a surface of the SiC substrate including an inner wall of the etch pit in such a manner that portions of the SiC growth layer grown on the inner wall of the etch pit join with each other.Type: ApplicationFiled: December 1, 2011Publication date: June 7, 2012Applicant: DENSO CORPORATIONInventors: Hiroki WATANABE, Yasuo KITOU, Yasushi FURUKAWA, Kensaku YAMAMOTO, Hidefumi TAKAYA, Masahiro SUGIMOTO, Yukihiko WATANABE, Narumasa SOEJIMA, Tsuyoshi ISHIKAWA
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Publication number: 20110203513Abstract: In a method of manufacturing a silicon carbide substrate, a defect-containing substrate made of silicon carbide is prepared. The defect-containing substrate has a front surface, a rear surface being opposite to the front surface, and a surface portion adjacent to the front surface. The detect-containing substrate includes a screw dislocation in the surface portion. The front surface of the defect-containing substrate is applied with an external force so that a crystallinity of the surface portion is reduced. After being applied with the external force, the defect-containing substrate is thermally treated so that the crystallinity of the surface portion is recovered.Type: ApplicationFiled: February 17, 2011Publication date: August 25, 2011Applicants: DENSO CORPORATION, TOYOTA JIDOSHA KABUSHIKI KAISHAInventors: Hiroki WATANABE, Yasuo Kitou, Kensaku Yamamoto, Hidefumi Takaya, Masahiro Sugimoto, Jun Morimoto, Yukihiko Watanabe, Narumasa Soejima, Tsuyoshi Ishikawa
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Publication number: 20110147493Abstract: A method is for forming a periodic groove arrangement. According to the method, a base material made of metal is provided. Furthermore, the periodic groove arrangement, which includes a plurality of periodic grooves, is formed on a surface of the base material by irradiating and scanning the surface of the base material with a pulsed laser. A fuel injection system includes a nozzle hole forming part and the periodic groove arrangement formed by the method. The nozzle hole forming part includes a nozzle hole, which passes through the nozzle hole forming part and through which fuel is injected. The periodic groove arrangement is formed on an outer surface of the nozzle hole forming part.Type: ApplicationFiled: December 17, 2010Publication date: June 23, 2011Applicant: DENSO CORPORATIONInventors: Yoshihito MITSUOKA, Kazunori Suzuki, Yasuo Kitou, Sumitomo Inomata
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Publication number: 20100307417Abstract: A manufacturing device of a silicon carbide single crystal includes: a reaction chamber; a seed crystal arranged in the reaction chamber; and a heating chamber. The seed crystal is disposed on an upper side of the reaction chamber, and the gas is supplied from an under side of the reaction chamber. The heating chamber is disposed on an upstream side of a flowing passage of the gas from the reaction chamber. The heating chamber includes a hollow cylindrical member, a raw material gas inlet, a raw material gas supply nozzle and multiple baffle plates. The inlet introduces the gas into the hollow cylindrical member. The nozzle discharges the gas from the hollow cylindrical member to the reaction chamber. The baffle plates are arranged on the flowing passage of the gas between the inlet and the nozzle.Type: ApplicationFiled: May 27, 2010Publication date: December 9, 2010Applicants: DENSO CORPORATION, LPE S.p.A.Inventors: Jun Kojima, Yasuo Kitou, Sonia De Angelis, Ambrogio Peccenati, Giuseppe Tarenzi
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Publication number: 20100199910Abstract: In a method of manufacturing a silicon carbide single crystal, a silicon carbide substrate having a surface of one of a (11-2n) plane and a (1-10n) plane, where n is any integer number greater than or equal to 0, is prepared. An epitaxial layer having a predetermined impurity concentration is grown on the one of the (11-2n) plane and the (1-10n) plane of the silicon carbide substrate by a chemical vapor deposition method so that a threading dislocation is discharged from a side surface of the epitaxial layer. A silicon carbide single crystal is grown into a bulk shape by a sublimation method on the one of the (11-2n) plane and the (1-10n) plane of the epitaxial layer from which the threading dislocation is discharged.Type: ApplicationFiled: February 9, 2010Publication date: August 12, 2010Applicant: DENSO CORPORATIONInventors: Hiroki WATANABE, Yasuo KITOU, Masami NAITO
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Publication number: 20100200866Abstract: A direction of a dislocation line of a threading dislocation is aligned, and an angle between the direction of the dislocation line of the threading dislocation and a [0001]-orientation c-axis is equal to or smaller than 22.5 degrees. The threading dislocation having the dislocation line along with the [0001]-orientation c-axis is perpendicular to a direction of a dislocation line of a basal plane dislocation. Accordingly, the dislocation does not provide an extended dislocation on the c-face, so that a stacking fault is not generated. Thus, when an electric device is formed in a SiC single crystal substrate having the direction of the dislocation line of the threading dislocation, which is the [0001]-orientation c-axis, a SiC semiconductor device is obtained such that device characteristics are excellent without deterioration, and a manufacturing yield ration is improved.Type: ApplicationFiled: January 21, 2010Publication date: August 12, 2010Applicant: DENSO CORPORATIONInventors: Yasuo Kitou, Hiroki Watanabe, Masanori Nagaya, Kensaku Yamamoto, Eiichi Okuno
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Publication number: 20090107394Abstract: A device for manufacturing a SiC single crystal includes: a raw material gas introduction pipe; a raw material gas heat chamber having a raw material gas supply passage for heating the gas in the passage; a reaction chamber having a second sidewall, an inner surface of which contacts an outer surface of a first sidewall of the heat chamber, and having a bottom, on which a SiC single crystal substrate is arranged; and a discharge pipe in a hollow center of the raw material gas heat chamber. The supply passage is disposed between an outer surface of the discharge pipe and an inner surface of the first sidewall. The discharge pipe discharges a residual gas, which is not used for crystal growth of the SiC single crystal.Type: ApplicationFiled: October 28, 2008Publication date: April 30, 2009Applicant: DENSO CORPORATIONInventors: Yasuo Kitou, Jun Kojima
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Patent number: 7314523Abstract: A method for manufacturing a SiC single crystal from a SiC seed crystal is provided. The method includes the steps of: measuring a diameter of the SiC single crystal during a crystal growth of the SiC single crystal; and controlling the diameter of the SiC single crystal to be a predetermined diameter on the basis of the measured diameter. The method provides the SiC single crystal with high quality and large size.Type: GrantFiled: August 26, 2005Date of Patent: January 1, 2008Assignee: DENSO CORPORATIONInventors: Kouki Futatsuyama, Yasuo Kitou
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Patent number: 7217323Abstract: A method for manufacturing a silicon carbide single crystal includes the steps of: setting a substrate as a seed crystal in a reactive chamber; introducing a raw material gas into the reactive chamber; growing a silicon carbide single crystal from the substrate; heating the gas at an upstream side from the substrate in a gas flow path; keeping a temperature of the substrate at a predetermined temperature lower than the gas so that the single crystal is grown from the substrate; heating a part of the gas, which is a non-reacted raw material gas and does not contribute to crystal growth, after passing through the substrate; and absorbing a non-reacted raw material gas component in the non-reacted raw material gas with an absorber.Type: GrantFiled: April 1, 2004Date of Patent: May 15, 2007Assignee: Denso CorporationInventors: Naohiro Sugiyama, Yasuo Kitou, Emi Makino, Kazukuni Hara, Kouki Futatsuyama, Atsuto Okamoto
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Publication number: 20060042540Abstract: A method for manufacturing a SiC single crystal from a SiC seed crystal is provided. The method includes the steps of: measuring a diameter of the SiC single crystal during a crystal growth of the SiC single crystal; and controlling the diameter of the SiC single crystal to be a predetermined diameter on the basis of the measured diameter. The method provides the SiC single crystal with high quality and large size.Type: ApplicationFiled: August 26, 2005Publication date: March 2, 2006Inventors: Kouki Futatsuyama, Yasuo Kitou
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Publication number: 20040194694Abstract: A method for manufacturing a silicon carbide single crystal includes the steps of: setting a substrate as a seed crystal in a reactive chamber; introducing a raw material gas into the reactive chamber; growing a silicon carbide single crystal from the substrate; heating the gas at an upstream side from the substrate in a gas flow path; keeping a temperature of the substrate at a predetermined temperature lower than the gas so that the single crystal is grown from the substrate; heating a part of the gas, which is a non-reacted raw material gas and does not contribute to crystal growth, after passing through the substrate; and absorbing a non-reacted raw material gas component in the non-reacted raw material gas with an absorber.Type: ApplicationFiled: April 1, 2004Publication date: October 7, 2004Applicant: DENSO CORPORATIONInventors: Naohiro Sugiyama, Yasuo Kitou, Emi Makino, Kazukuni Hara, Kouki Futatsuyama, Atsuto Okamoto
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Patent number: 5952679Abstract: A plurality of grooves are formed in a SiC substrate consisting of an n.sup.- -type epitaxial layer and a p-type epitaxial layer layered on the surface of an n.sup.+ -type monocrystalline SiC semiconductor substrate. These grooves are formed in a grid on the SiC substrate. Heat treatment is then carried out to straighten warp of the SiC substrate caused by the growth of the epitaxial layers.Type: GrantFiled: October 16, 1997Date of Patent: September 14, 1999Assignee: Denso CorporationInventors: Yasuo Kitou, Eiji Kitaoka, Takamasa Suzuki, Mitsuhiro Kataoka
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Patent number: 5944890Abstract: In a method of producing single crystals on a seed crystal, the seed crystal is covered by a protection layer except for a surface on which the single crystals are to be formed. The protection layer is made of material such as carbon or the like, which is stable in a step of forming the single crystals. As a result, a temperature gradient and mass transfer in the seed crystal can be prevented, whereby quality of the single crystals formed on the seed crystal can be improved.Type: GrantFiled: March 28, 1997Date of Patent: August 31, 1999Assignee: Denso CorporationInventors: Yasuo Kitou, Naohiro Sugiyama, Atsuto Okamoto, Toshihiko Tani, Nobuo Kamiya