Patents by Inventor Kazuhiko Kusunoki
Kazuhiko Kusunoki 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: 20160053402Abstract: The present invention provides a method for producing a SiC single crystal, which allows improving the quality of the single crystal even when crystal growth is performed by forming a meniscus. A growth step in the production method according to the present embodiment comprises a forming step and a first maintenance step. In the forming step, a meniscus is formed between a growth interface of a SiC single crystal and a liquid surface of a Si—C solution. In the first maintenance step, the fluctuation range of the height of the meniscus is maintained within a predetermined range by moving at least one of a seed shaft and a crucible relative to the other in the height direction.Type: ApplicationFiled: April 9, 2014Publication date: February 25, 2016Inventors: Kazuhiko KUSUNOKI, Kazuhito KAMEI, Hironori DAIKOKU, Hidemitsu SAKAMOTO, Motohisa KADO
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Patent number: 9222198Abstract: A SiC single crystal wafer on which a good quality epitaxial film by suppressing defects derived from the wafer can be grown has an affected surface layer with a thickness of at most 50 nm and a SiC single crystal portion with an oxygen content of at most 1.0×1017 atoms/cm3. This SiC single crystal wafer is manufactured from a high purity SiC bulk single crystal obtained by the solution growth method using raw materials with an oxygen content of at most 100 ppm and a non-oxidizing atmosphere having an oxygen concentration of at most 100 ppm.Type: GrantFiled: February 27, 2012Date of Patent: December 29, 2015Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Kazuhiko Kusunoki, Kazuhito Kamei, Nobuyoshi Yashiro, Junichi Koike
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Publication number: 20150299900Abstract: The purpose of the present invention is to produce a high-quality SiC single crystal with good reproducibility while avoiding the fluctuations in the solution-contacting position of a seed crystal among production operations. A method for producing a SiC single crystal by bringing a SiC seed crystal supported by a supporting bar into contact with a solution that has been heated by high-frequency induction to thereby grow the SiC single crystal, wherein the supporting bar is born down while applying a magnetic field to the solution to thereby bring the SiC seed crystal into contact with the solution, and subsequently the application of the magnetic field is halted to grow the SiC single crystal.Type: ApplicationFiled: November 11, 2013Publication date: October 22, 2015Applicant: TOYOTA JIDOSHA KABUSHIKI KAISHAInventors: Hironori DAIKOKU, Hidemitsu SAKAMOTO, Motohisa KADO, Kazuhiko KUSUNOKI
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Publication number: 20150225871Abstract: A SiC single crystal production apparatus is used in production of SiC single crystals by solution growth techniques. The apparatus includes: a seed shaft having a lower end surface to which a SiC seed crystal is to be attached; a crucible that contains a Si—C solution; a stirring member that is immersed in the Si—C solution; and drive sources that cause relative rotation between the crucible and the stirring member. The lower end of the stirring member is located lower than the lower end of the SiC seed crystal attached to the lower end surface of the seed shaft.Type: ApplicationFiled: September 2, 2013Publication date: August 13, 2015Applicant: TOYOTA JIDOSHA KABUSHIKI KAISHAInventors: Kazuhiko Kusunoki, Kazuhito Kamei, Nobuyoshi Yashiro, Nobuhiro Okada, Koji Moriguchi, Motohisa Kado, Hironori Daikoku, Hidemitsu Sakamoto
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Publication number: 20150225872Abstract: The production apparatus is used in production of single crystals by solution growth techniques. The production apparatus includes a seed shaft, a crucible, and a drive source. The seed shaft has a lower end surface to which a seed crystal is to be attached. The crucible contains a solution from which a single crystal is made. The drive source causes the crucible to rotate, and also varies the rotational speed of the crucible. The inner peripheral surface of the crucible includes a flow control surface which defines a non-circular cross-sectional shape. This single crystal production apparatus is capable of strongly stirring the solution contained in the crucible.Type: ApplicationFiled: August 30, 2013Publication date: August 13, 2015Applicant: TOYOTA JIDOSHA KABUSHIKI KAISHAInventors: Kazuhito Kamei, Kazuhiko Kusunoki, Nobuyoshi Yashiro, Nobuhiro Okada, Koji Moriguchi, Hironori Daikoku, Motohisa Kado, Hidemitsu Sakamoto
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Publication number: 20150221511Abstract: Provided is a method for producing an SiC single crystal, which is capable of greatly increasing the growth rate in a solution technique in comparison to conventional methods. A method for producing an SiC single crystal, wherein an SiC single crystal is grown by bringing a seed crystal substrate into contact with an Si—C solution that is put in a crucible and has a temperature gradient decreasing from the inside to the liquid level, and wherein the value of depth/inner diameter of the crucible is less than 1.71 and the temperature gradient of the Si—C solution from the liquid level to 10 mm below the liquid level is larger than 42° C./cm.Type: ApplicationFiled: August 12, 2013Publication date: August 6, 2015Inventors: Motohisa Kado, Kazuhiko Kusunoki, Kazuhito Kamei
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Publication number: 20150191848Abstract: A production apparatus is used for a solution growth method. The production apparatus includes a seed shaft and a crucible. The seed shaft has a lower end surface to which an SiC seed crystal is attached. The crucible contains an SiC solution. The crucible includes a cylindrical portion, a bottom portion, and an inner lid. The bottom portion is disposed at a lower end of the cylindrical portion. The inner lid is disposed in the cylindrical portion. The inner lid has a through hole and is positioned below a liquid surface of the SiC solution when the SiC solution is contained in the crucible.Type: ApplicationFiled: July 15, 2013Publication date: July 9, 2015Applicant: TOYOTA JIDOSHA KABUSHIKI KAISHAInventors: Nobuyoshi Yashiro, Kazuhito Kamei, Kazuhiko Kusunoki, Nobuhiro Okada, Koji Moriguchi, Hironori Daikoku, Hidemitsu Sakamoto, Motohisa Kado
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Publication number: 20150167196Abstract: Provided are: a high-quality SiC single crystal ingot that suppresses the generation of inclusions; and a production method for said SiC single crystal ingot. The present invention pertains to a SiC single crystal ingot including a seed crystal substrate and a SiC growth crystal grown using the solution method and using the seed crystal substrate as the origin thereof, the growth crystal having a recessed crystal growth surface and not including inclusions.Type: ApplicationFiled: May 8, 2013Publication date: June 18, 2015Inventors: Motohisa Kado, Hironori Daikoku, Hidemitsu Sakamoto, Kazuhiko Kusunoki, Nobuhiro Okada
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Publication number: 20150152569Abstract: An apparatus (10) for producing an SiC single crystal is used in the solution growth includes a seed shaft (28) and a crucible (14). The seed shaft (28) has a lower end surface (28S) to which an SiC seed crystal (32) is to be attached. The crucible (14) holds an Si—C solution (15). The seed shaft (28) includes a cylinder part (28A), a bottom part (28B), and a low heat conductive member (28C). The bottom part (28B) is located at the lower end of the cylinder part (28A) and has the lower end surface (28S). The low heat conductive member (28C) is arranged on the upper surface of the bottom part (28B) and has a thermal conductivity lower than that of the bottom part (28B). This production apparatus can make the temperature within the crystal growth surface of the SiC seed crystal less liable to vary.Type: ApplicationFiled: July 10, 2013Publication date: June 4, 2015Inventors: Nobuhiro Okada, Kazuhito Kamei, Kazuhiko Kusunoki, Nobuyoshi Yashiro, Koji Moriguchi, Hironori Daikoku, Motohia Kado, Hidemitsu Sakamoto
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Publication number: 20150136016Abstract: Provided is a method for producing a SiC single crystal wherein generation of polycrystals can be inhibited even if the temperature of the Si—C solution is changed after seed touching.Type: ApplicationFiled: November 14, 2014Publication date: May 21, 2015Inventors: Katsunori DANNO, Kazuhiko KUSUNOKI, Kazuhito KAMEI
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Publication number: 20150075419Abstract: A method for producing a SiC single crystal having a large growth thickness of 10 mm or greater by a solution process is provided. This is achieved by a method for producing a SiC single crystal, wherein a SiC seed crystal substrate is contacted with a Si—C solution with a temperature gradient, in which the temperature decreases from the interior toward the surface, to grow a SiC single crystal, and wherein the temperature gradient in the surface region of the Si—C solution is increased at least once while the SiC single crystal is grown with the (000-1) face as the growth surface, to grow a SiC single crystal having a growth thickness of 10 mm or greater.Type: ApplicationFiled: September 11, 2014Publication date: March 19, 2015Inventors: Motohisa Kado, Hironori Daikoku, Kazuhiko Kusunoki, Kazuhito Kamei
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Publication number: 20150013590Abstract: The aim of the present invention is to provide a seed crystal holding shaft that is used in a device for producing single crystals by a solution process that allows for faster growth of SiC single crystals than in the past, and a method for producing single crystals by the solution process. The seed crystal holding shaft used in a device for producing single crystals by the solution process is a seed crystal holding shaft wherein at least a portion of a side of the seed crystal holding shaft is covered by a reflectance member having a higher reflectance than the reflectance of the seed crystal holding shaft and the reflector member is disposed such that there is a space between the reflector member and the seed crystals held on the end face of the seed crystal holding shaft.Type: ApplicationFiled: December 27, 2012Publication date: January 15, 2015Applicants: TOYOTA JIDOSHA KABUSHIKI KAISHA, NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Motohisa Kado, Kazuhiko Kusunoki
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Publication number: 20140245945Abstract: Provided is a SiC single crystal manufacturing method whereby growing speed improvement required to have high productivity can be achieved, while maintaining flat growth in which uniform single crystal growth can be continued at the time of growing a SiC single crystal using a solution method. In this SiC single crystal manufacturing method, a SiC single crystal is grown in a crucible from a Si solution containing C. The SiC single crystal manufacturing method is characterized in alternately repeating: a high supersaturation degree growing period, in which the growth is promoted by maintaining the supersaturation degree of C in the Si solution higher than an upper limit critical value at which flat growth can be maintained, said supersaturation degree being at a growing interface between the Si solution and a SiC single crystal being grown; and a low supersaturation degree growing period, in which the growth is promoted by maintaining the supersaturation degree lower than the critical value.Type: ApplicationFiled: December 9, 2011Publication date: September 4, 2014Applicants: TOYOTA JIDOSHA KABUSHIKI KAISHA, NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Motohisa Kado, Hironori Daikoku, Kazuhiko Kusunoki
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Publication number: 20140116324Abstract: An apparatus for producing an SiC single crystal includes a crucible for accommodating an Si—C solution and a seed shaft having a lower end surface where an SiC seed crystal (36) would be attached. The seed shaft includes an inner pipe that extends in a height direction of the crucible and has a first passage. An outer pipe accommodates the inner pipe and constitutes a second passage between itself and the inner pipe and has a bottom portion whose lower end surface covers a lower end opening of the outer pipe. One passage of the first and second passages serves as an introduction passage where coolant gas flows downward, and the other passage serves as a discharge passage where coolant gas flows upward. A region inside the pipe that constitutes the introduction passage is to be overlapped by a region of not less than 60% of the SiC seed crystal.Type: ApplicationFiled: June 15, 2012Publication date: May 1, 2014Applicants: TOYOTA JIDOSHA KABUSHIKI KAISHA, NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Kazuhiko Kusunoki, Kazuhito Kamei, Nobuyoshi Yashiro, Nobuhiro Okada, Hironori Daikoku, Motohisa Kado, Hidemitsu Sakamoto
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Publication number: 20140116325Abstract: A region of an SiC solution in the vicinity of an SiC seed crystal is cooled while suppressing the temperature variation in a peripheral region of the SiC solution. An apparatus includes a seed shaft and a crucible for an SiC solution. The seed shaft has a lower end surface for attachment to an SiC seed crystal. The crucible comprises a main body, an intermediate cover, and a top cover. The main body includes a first cylindrical portion and a bottom portion at a lower end portion of the first cylindrical portion. The intermediate cover is within the first cylindrical portion and above the liquid level of the SiC solution in the main body. The intermediate cover has a first through hole for the seed shaft. The top cover is disposed above the intermediate cover and has a second through hole for the seed shaft to pass through.Type: ApplicationFiled: June 11, 2012Publication date: May 1, 2014Applicants: TOYOTA JIDOSHA KABUSHIKI KAISHA, NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Kazuhito Kamei, Kazuhiko Kusunoki, Nobuyoshi Yashiro, Nobuhiro Okada, Hironori Daikoku, Motohisa Kado, Hidamisu Kasamoto
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Publication number: 20130305981Abstract: A manufacturing apparatus of a SiC single crystal which can suppress the generation of a polycrystal is provided. A jig (41) and a crucible (6) are accommodated in a chamber (1). A SiC solution (8) is housed in the crucible (6). The jig (41) includes a seed shaft (411) and a cover member (412). The seed shaft (411) can move up and down, and a SiC seed crystal (9) is attached to the lower surface thereof. The cover member (412) is attached to the lower end portion of the seed shaft (411). The cover member (412) is a housing which has an opening at its lower end, wherein the lower end portion of the seed shaft (411) is disposed in the cover member (412).Type: ApplicationFiled: December 26, 2011Publication date: November 21, 2013Applicants: TOYOTA JIDOSHA KABUSHIKI KAISHA, NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Kazuhito Kamei, Kazuhiko Kusunoki, Nobuyoshi Yashiro, Nobuhiro Okada, Motohisa Kado, Hidemitsu Sakamoto, Hironori Daikoku
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Publication number: 20130220212Abstract: A method for manufacturing an n-type SiC single crystal, enables the suppression of the variation in nitrogen concentration among a plurality of n-type SiC single crystal ingots manufactured. A method includes the steps of: providing a manufacturing apparatus (100) including a chamber (1) having an area in which a crucible (7) is to be disposed; heating the area in which the crucible (7) is to be disposed and evacuating the gas in the chamber (1); filling, after the evacuation, the chamber (1) with a mixed gas containing a noble gas and nitrogen gas; heating and melting a starting material housed in the crucible (7) disposed in the area to produce a SiC solution (8) containing silicon and carbon; and immersing a SiC seed crystal into the SiC solution under the mixed gas atmosphere to grow an n-type SiC single crystal on the SiC seed crystal.Type: ApplicationFiled: November 4, 2011Publication date: August 29, 2013Applicants: TOYOTA JIDOSHA KABUSHIKI KAISHA, NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Kazuhiko Kusunoki, Kazuhito Kamei, Nobuyoshi Yashiro, Kouji Moriguchi, Nobuchiro Okada, Katsunori Danno, Hironori Daikoku
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Patent number: 8492774Abstract: A manufacturing method for a SiC single crystal film which allows stable growth of a SiC epitaxial film with a low doping concentration on a substrate with a diameter of at least 2 inches by the LPE method using a SiC solution in solvent of a melt includes an evacuation step in which the interior of a crystal growth furnace is evacuated with heating until the vacuum pressure at the crystal growth temperature is 5×10?3 Pa or lower prior to introducing a raw material for the melt into the furnace. Then, a crucible containing a raw material for the melt is introduced into the furnace, a SiC solution is formed, and a SiC epitaxial film is grown on a substrate immersed in the solution.Type: GrantFiled: February 24, 2011Date of Patent: July 23, 2013Assignees: Nippon Steel & Sumitomo Metal Corporation, Mitsubishi Electric CorporationInventors: Kazuhiko Kusunoki, Kazuhito Kamei, Nobuyoshi Yashiro, Ryo Hattori
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Patent number: 8388752Abstract: A method capable of stably manufacturing a SiC single crystal in the form of a thin film or a bulk crystal having a low carrier density of at most 5×1017/cm3 and preferably less than 1×1017/cm3 and which is suitable for use in various devices by liquid phase growth using a SiC solution in which the solvent is a melt of a Si alloy employs a Si alloy having a composition which is expressed by SixCryTiz wherein x, y, and z (each in atomic percent) satisfy 0.50<x<0.68, 0.08<y<0.35, and 0.08<z<0.35, or ??(1) 0.40<x?0.50, 0.15<y<0.40, and 0.15<z<0.35.??(2) x, y, and z preferably satisfy 0.53<x<0.65, 0.1<y<0.3, and 0.1<z<0.3.Type: GrantFiled: February 28, 2011Date of Patent: March 5, 2013Assignee: Sumitomo Metal Industries, Ltd.Inventors: Kazuhito Kamei, Kazuhiko Kusunoki, Nobuyoshi Yashiro, Akihiro Yauchi, Shinji Shimosaki
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Publication number: 20120211769Abstract: A SiC single crystal wafer on which a good quality epitaxial film by suppressing defects derived from the wafer can be grown has an affected surface layer with a thickness of at most 50 nm and a SiC single crystal portion with an oxygen content of at most 1.0×1017 atoms/cm3. This SiC single crystal wafer is manufactured from a high purity SiC bulk single crystal obtained by the solution growth method using raw materials with an oxygen content of at most 100 ppm and a non-oxidizing atmosphere having an oxygen concentration of at most 100 ppm.Type: ApplicationFiled: February 27, 2012Publication date: August 23, 2012Applicant: SUMITOMO METAL INDUSTRIES, LTD.Inventors: Kazuhiko Kusunoki, Kazuhito Kamei, Nobuyoshi Yashiro, Junichi Koike