Patents by Inventor Yuji Kagamitani
Yuji Kagamitani 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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Publication number: 20220033992Abstract: A high-quality nitride crystal can be produced efficiently by charging a nitride crystal starting material that contains tertiary particles having a maximum diameter of from 1 to 120 mm and formed through aggregation of secondary particles having a maximum diameter of from 100 to 1000 ?m, in the starting material charging region of a reactor, followed by crystal growth in the presence of a solvent in a supercritical state and/or a subcritical state in the reactor, wherein the nitride crystal starting material is charged in the starting material charging region in a bulk density of from 0.7 to 4.5 g/cm3 for the intended crystal growth.Type: ApplicationFiled: September 27, 2021Publication date: February 3, 2022Applicant: MITSUBISHI CHEMICAL CORPORATIONInventors: Yutaka MIKAWA, Hideo FUJISAWA, Kazunori KAMADA, Hirobumi NAGAOKA, Shinichiro KAWABATA, Yuji KAGAMITANI
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Patent number: 11162190Abstract: A high-quality nitride crystal can be produced efficiently by charging a nitride crystal starting material that contains tertiary particles having a maximum diameter of from 1 to 120 mm and formed through aggregation of secondary particles having a maximum diameter of from 100 to 1000 ?m, in the starting material charging region of a reactor, followed by crystal growth in the presence of a solvent in a supercritical state and/or a subcritical state in the reactor, wherein the nitride crystal starting material is charged in the starting material charging region in a bulk density of from 0.7 to 4.5 g/cm3 for the intended crystal growth.Type: GrantFiled: October 28, 2019Date of Patent: November 2, 2021Assignee: MITSUBISHI CHEMICAL CORPORATIONInventors: Yutaka Mikawa, Hideo Fujisawa, Kazunori Kamada, Hirobumi Nagaoka, Shinichiro Kawabata, Yuji Kagamitani
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Publication number: 20200109489Abstract: A high-quality nitride crystal can be produced efficiently by charging a nitride crystal starting material that contains tertiary particles having a maximum diameter of from 1 to 120 mm and formed through aggregation of secondary particles having a maximum diameter of from 100 to 1000 ?m, in the starting material charging region of a reactor, followed by crystal growth in the presence of a solvent in a supercritical state and/or a subcritical state in the reactor, wherein the nitride crystal starting material is charged in the starting material charging region in a bulk density of from 0.7 to 4.5 g/cm3 for the intended crystal growth.Type: ApplicationFiled: October 28, 2019Publication date: April 9, 2020Applicant: MITSUBISHI CHEMICAL CORPORATIONInventors: Yutaka MIKAWA, Hideo FUJISAWA, Kazunori KAMADA, Hirobumi NAGAOKA, Shinichiro KAWABATA, Yuji KAGAMITANI
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Patent number: 10526726Abstract: A high-quality nitride crystal can be produced efficiently by charging a nitride crystal starting material that contains tertiary particles having a maximum diameter of from 1 to 120 mm and formed through aggregation of secondary particles having a maximum diameter of from 100 to 1000 ?m, in the starting material charging region of a reactor, followed by crystal growth in the presence of a solvent in a supercritical state and/or a subcritical state in the reactor, wherein the nitride crystal starting material is charged in the starting material charging region in a bulk density of from 0.7 to 4.5 g/cm3 for the intended crystal growth.Type: GrantFiled: November 9, 2016Date of Patent: January 7, 2020Assignee: MITSUBISHI CHEMICAL CORPORATIONInventors: Yutaka Mikawa, Hideo Fujisawa, Kazunori Kamada, Hirobumi Nagaoka, Shinichiro Kawabata, Yuji Kagamitani
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Patent number: 10501865Abstract: A first object of the present invention is to provide a method for efficiently growing a nitride single crystal even under low pressure conditions. The present invention relates to a method for producing a nitride single crystal, comprising growing a nitride crystal on the surface of a seed crystal having a hexagonal crystal structure by setting a pressure in a reaction vessel having the seed crystal, a nitrogen-containing solvent, a mineralizer containing a fluorine atom, and a raw material placed therein to 5 to 200 MPa and performing control so that the nitrogen-containing solvent is in at least either a supercritical state or a subcritical state.Type: GrantFiled: March 1, 2018Date of Patent: December 10, 2019Assignees: Mitsubishi Chemical Corporation, Tohoku University, The Japan Steel Works, Ltd.Inventors: Tohru Ishiguro, Quanxi Bao, Chiaki Yokoyama, Daisuke Tomida, Shigefusa Chichibu, Rinzo Kayano, Mutsuo Ueda, Makoto Saito, Yuji Kagamitani
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Publication number: 20180187328Abstract: A first object of the present invention is to provide a method for efficiently growing a nitride single crystal even under low pressure conditions. The present invention relates to a method for producing a nitride single crystal, comprising growing a nitride crystal on the surface of a seed crystal having a hexagonal crystal structure by setting a pressure in a reaction vessel having the seed crystal, a nitrogen-containing solvent, a mineralizer containing a fluorine atom, and a raw material placed therein to 5 to 200 MPa and performing control so that the nitrogen-containing solvent is in at least either a supercritical state or a subcritical state.Type: ApplicationFiled: March 1, 2018Publication date: July 5, 2018Applicants: Mitsubishi Chemical Corporation, Tohoku University, The Japan Steel Works, Ltd.Inventors: Tohru Ishiguro, Quanxi Bao, Chiaki Yokoyama, Daisuke Tomida, Shigefusa Chichibu, Rinzo Kayano, Mutsuo Ueda, Makoto Saito, Yuji Kagamitani
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Patent number: 9976229Abstract: A first object of the present invention is to provide a method for efficiently growing a nitride single crystal even under low pressure conditions. The present invention relates to a method for producing a nitride single crystal, comprising growing a nitride crystal on the surface of a seed crystal having a hexagonal crystal structure by setting a pressure in a reaction vessel having the seed crystal, a nitrogen-containing solvent, a mineralizer containing a fluorine atom, and a raw material placed therein to 5 to 200 MPa and performing control so that the nitrogen-containing solvent is in at least either a supercritical state or a subcritical state.Type: GrantFiled: September 29, 2014Date of Patent: May 22, 2018Assignees: MITSUBISHI CHEMICAL CORPORATION, TOHOKU UNIVERSITY, THE JAPAN STEEL WORKS, LTD.Inventors: Tohru Ishiguro, Quanxi Bao, Chiaki Yokoyama, Daisuke Tomida, Shigefusa Chichibu, Rinzo Kayano, Mutsuo Ueda, Makoto Saito, Yuji Kagamitani
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Publication number: 20170051434Abstract: A high-quality nitride crystal can be produced efficiently by charging a nitride crystal starting material that contains tertiary particles having a maximum diameter of from 1 to 120 mm and formed through aggregation of secondary particles having a maximum diameter of from 100 to 1000 ?m, in the starting material charging region of a reactor, followed by crystal growth in the presence of a solvent in a supercritical state and/or a subcritical state in the reactor, wherein the nitride crystal starting material is charged in the starting material charging region in a bulk density of from 0.7 to 4.5 g/cm3 for the intended crystal growth.Type: ApplicationFiled: November 9, 2016Publication date: February 23, 2017Applicant: MITSUBISHI CHEMICAL CORPORATIONInventors: Yutaka MIKAWA, Hideo FUJISAWA, Kazunori KAMADA, Hirobumi NAGAOKA, Shinichiro KAWABATA, Yuji KAGAMITANI
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Patent number: 9518337Abstract: A high-quality nitride crystal can be produced efficiently by charging a nitride crystal starting material that contains tertiary particles having a maximum diameter of from 1 to 120 mm and formed through aggregation of secondary particles having a maximum diameter of from 100 to 1000 ?m, in the starting material charging region of a reactor, followed by crystal growth in the presence of a solvent in a supercritical state and/or a subcritical state in the reactor, wherein the nitride crystal starting material is charged in the starting material charging region in a bulk density of from 0.7 to 4.5 g/cm3 for the intended crystal growth.Type: GrantFiled: May 15, 2015Date of Patent: December 13, 2016Assignee: MITSUBISHI CHEMICAL CORPORATIONInventors: Yutaka Mikawa, Hideo Fujisawa, Kazunori Kamada, Hirobumi Nagaoka, Shinichiro Kawabata, Yuji Kagamitani
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Patent number: 9192910Abstract: To grow a highly pure nitride crystal having a low oxygen concentration efficiently by an ammonothermal method. A process for producing a nitride crystal, which comprises bringing a reactant gas reactive with ammonia to form a mineralizer, and ammonia into contact with each other to prepare a mineralizer in a reactor or in a closed circuit connected to a reactor; and growing a nitride crystal by an ammonothermal method in the presence of the ammonia and the mineralizer.Type: GrantFiled: January 7, 2010Date of Patent: November 24, 2015Assignees: Mitsubishi Chemical Corporation, Tohoku UniversityInventors: Yutaka Mikawa, Makiko Kiyomi, Yuji Kagamitani, Toru Ishiguro
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Publication number: 20150247256Abstract: A high-quality nitride crystal can be produced efficiently by charging a nitride crystal starting material that contains tertiary particles having a maximum diameter of from 1 to 120 mm and formed through aggregation of secondary particles having a maximum diameter of from 100 to 1000 ?m, in the starting material charging region of a reactor, followed by crystal growth in the presence of a solvent in a supercritical state and/or a subcritical state in the reactor, wherein the nitride crystal starting material is charged in the starting material charging region in a bulk density of from 0.7 to 4.5 g/cm3 for the intended crystal growth.Type: ApplicationFiled: May 15, 2015Publication date: September 3, 2015Applicant: MITSUBISHI CHEMICAL CORPORATIONInventors: Yutaka MIKAWA, Hideo FUJISAWA, Kazunori KAMADA, Hirobumi NAGAOKA, Shinichiro KAWABATA, Yuji KAGAMITANI
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Patent number: 9096945Abstract: A high-quality nitride crystal can be produced efficiently by charging a nitride crystal starting material that contains tertiary particles having a maximum diameter of from 1 to 120 mm and formed through aggregation of secondary particles having a maximum diameter of from 100 to 1000 ?m, in the starting material charging region of a reactor, followed by crystal growth in the presence of a solvent in a supercritical state and/or a subcritical state in the reactor, wherein the nitride crystal starting material is charged in the starting material charging region in a bulk density of from 0.7 to 4.5 g/cm3 for the intended crystal growth.Type: GrantFiled: October 26, 2012Date of Patent: August 4, 2015Assignee: MITSUBISHI CHEMICAL CORPORATIONInventors: Yutaka Mikawa, Hideo Fujisawa, Kazunori Kamada, Hirobumi Nagaoka, Shinichiro Kawabata, Yuji Kagamitani
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Publication number: 20150023862Abstract: A first object of the present invention is to provide a method for efficiently growing a nitride single crystal even under low pressure conditions. The present invention relates to a method for producing a nitride single crystal, comprising growing a nitride crystal on the surface of a seed crystal having a hexagonal crystal structure by setting a pressure in a reaction vessel having the seed crystal, a nitrogen-containing solvent, a mineralizer containing a fluorine atom, and a raw material placed therein to 5 to 200 MPa and performing control so that the nitrogen-containing solvent is in at least either a supercritical state or a subcritical state.Type: ApplicationFiled: September 29, 2014Publication date: January 22, 2015Applicants: Mitsubishi Chemical Corporation, Tohoku University, The Japan Steel Works, Ltd.Inventors: Toru ISHIGURO, Quanxi BAO, Chiaki YOKOYAMA, Daisuke TOMIDA, Shigefusa CHICHIBU, Rinzo KAYANO, Mutsuo UEDA, Makoto SAITO, Yuji KAGAMITANI
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Patent number: 8609059Abstract: To provide a production method for a nitride crystal, where a nitride crystal can be prevented from precipitating in a portion other than on a seed crystal and the production efficiency of a gallium nitride single crystal grown on the seed crystal can be enhanced. In a method for producing a nitride crystal by an ammonothermal method in a vessel containing a mineralizer-containing solution, out of the surfaces of said vessel and a member provided in said vessel, at least a part of the portion coming into contact with said solution is constituted by a metal or alloy containing one or more atoms selected from the group consisting of tantalum (Ta), tungsten (W) and titanium (Ti), and has a surface roughness (Ra) of less than 1.80 ?m.Type: GrantFiled: May 29, 2012Date of Patent: December 17, 2013Assignees: Mitsubishi Chemical Corporation, Tohoku University, The Japan Steel Works, Ltd.Inventors: Yutaka Mikawa, Makiko Kiyomi, Yuji Kagamitani, Toru Ishiguro, Yoshihiko Yamamura
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Publication number: 20130108537Abstract: A high-quality nitride crystal can be produced efficiently by charging a nitride crystal starting material that contains tertiary particles having a maximum diameter of from 1 to 120 mm and formed through aggregation of secondary particles having a maximum diameter of from 100 to 1000 ?m, in the starting material charging region of a reactor, followed by crystal growth in the presence of a solvent in a supercritical state and/or a subcritical state in the reactor, wherein the nitride crystal starting material is charged in the starting material charging region in a bulk density of from 0.7 to 4.5 g/cm3 for the intended crystal growth.Type: ApplicationFiled: October 26, 2012Publication date: May 2, 2013Inventors: Yutaka MIKAWA, Hideo FUJISAWA, Kazunori KAMADA, Hirobumi NAGAOKA, Shinichiro KAWABATA, Yuji KAGAMITANI
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Publication number: 20120237431Abstract: To provide a production method for a nitride crystal, where a nitride crystal can be prevented from precipitating in a portion other than on a seed crystal and the production efficiency of a gallium nitride single crystal grown on the seed crystal can be enhanced. In a method for producing a nitride crystal by an ammonothermal method in a vessel containing a mineralizer-containing solution, out of the surfaces of said vessel and a member provided in said vessel, at least a part of the portion coming into contact with said solution is constituted by a metal or alloy containing one or more atoms selected from the group consisting of tantalum (Ta), tungsten (W) and titanium (Ti), and has a surface roughness (Ra) of less than 1.80 ?m.Type: ApplicationFiled: May 29, 2012Publication date: September 20, 2012Applicants: MITSUBISHI CHEMICAL CORPORATION, THE JAPAN STEEL WORKS, LTD., TOHOKU UNIVERSITYInventors: YUTAKA MIKAWA, MAKIKO KIYOMI, YUJI KAGAMITANI, TORU ISHIGURO, YOSHIHIKO YAMAMURA
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Publication number: 20110268645Abstract: To grow a highly pure nitride crystal having a low oxygen concentration efficiently by an ammonothermal method. A process for producing a nitride crystal, which comprises bringing a reactant gas reactive with ammonia to form a mineralizer, and ammonia into contact with each other to prepare a mineralizer in a reactor or in a closed circuit connected to a reactor; and growing a nitride crystal by an ammonothermal method in the presence of the ammonia and the mineralizer.Type: ApplicationFiled: January 7, 2010Publication date: November 3, 2011Applicants: TOHOKU UNIVERSITY, MITSUBISHI CHEMICAL CORPORATIONInventors: Yutaka Mikawa, Makiko Kiyomi, Yuji Kagamitani, Toru Ishiguro
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Publication number: 20100104495Abstract: A method for producing a nitride semiconductor, comprising controlling temperature and pressure in a autoclave containing a seed having a hexagonal crystal structure, a nitrogen element-containing solvent, a raw material substance containing a metal element of Group 13 of the Periodic Table, and a mineralizer so as to put said solvent into a supercritical state and/or a subcritical state and thereby ammonothermally grow a nitride semiconductor crystal on the surface of said seed, wherein the crystal growth rate in the m-axis direction on said seed is 1.5 times or more the crystal growth rate in the c-axis direction on said seed. By the method, a nitride semiconductor having a large-diameter C plane or a nitride semiconductor thick in the m-axis direction can be efficiently and simply produced.Type: ApplicationFiled: October 10, 2007Publication date: April 29, 2010Applicants: MITSUBISHI CHEMICAL CORPORATION, TOHOKU UNIVERSITYInventors: Shinichiro Kawabata, Hirohisa Itoh, Dirk Ehrentraut, Yuji Kagamitani, Akira Yoshikawa, Tsuguo Fukuda
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Publication number: 20090165702Abstract: It is an object of the present invention to provide a self-coated single crystal that without any special step conducted after crystal growth, has its circumference coated with a layer of different properties. A self-coated single crystal according to the present invention is characterized in that in operations comprising melting crystal materials for a core and a clad in a single crucible and carrying out growth of a single crystal through a pulling up method or a pulling down method, a grown single crystal in an as-growth condition has its circumference self-coated with a clad whose refractive index is lower than that of the core.Type: ApplicationFiled: November 28, 2008Publication date: July 2, 2009Applicant: FUKUDA CRYSTAL LABORATORYInventors: Tsuguo FUKUDA, Akira Yoshikawa, Yuji Kagamitani
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CRYSTAL PRODUCTION PROCESS USING SUPERCRITICAL SOLVENT, CRYSTAL GROWTH APPARATUS, CRYSTAL AND DEVICE
Publication number: 20090092536Abstract: To control the precipitation position of a crystal and increase the yield of the crystal by performing the crystal growth according to the solvothermal method while allowing a predetermined amount of a substance differing in the critical density from the solvent to be present in the reaction vessel; and to prevent mixing of an impurity into the crystal and improve the crystal purity.Type: ApplicationFiled: June 29, 2006Publication date: April 9, 2009Applicants: TOHOKU UNIVERSITY, MITSUBISHI CHEMICAL CORPORATIONInventors: Shinichiro Kawabata, Akira Yoshikawa, Yuji Kagamitani, Tsuguo Fukuda