Patents by Inventor Shunsaku UETA
Shunsaku UETA 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: 20240145229Abstract: A silicon carbide substrate includes a first main surface, a second main surface, and an outer peripheral surface. When a defect, in the first main surface, observed using a mirror electron microscope while irradiating the first main surface with an ultraviolet ray is a first defect and a defect, in the first main surface, observed using molten potassium hydroxide is a second defect, a value obtained by dividing an area density of the first defect by an area density of the second defect is more than 0.9 and less than 1.2. The first defect consists of a first blind scratch, a first basal plane dislocation spaced apart from the first blind scratch, a second basal plane dislocation in contact with the first blind scratch, and a second blind scratch spaced apart from each of the first basal plane dislocation and the second basal plane dislocation.Type: ApplicationFiled: November 9, 2021Publication date: May 2, 2024Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.Inventors: Kyoko OKITA, Tsubasa HONKE, Shunsaku UETA
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Publication number: 20240136403Abstract: A silicon carbide substrate includes a first main surface, a second main surface, a threading screw dislocation, and a blind scratch. The second main surface is located opposite to the first main surface. The threading screw dislocation extends to each of the first main surface and the second main surface. The blind scratch is exposed at the first main surface and extends linearly as viewed in a direction perpendicular to the first main surface. A value obtained by dividing an area density of the blind scratch by an area density of threading screw dislocation is smaller than 0.13.Type: ApplicationFiled: November 24, 2021Publication date: April 25, 2024Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.Inventors: Kyoko OKITA, Tsubasa HONKE, Shunsaku UETA
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Patent number: 11913135Abstract: A silicon carbide substrate has a first main surface and a second main surface opposite to the first main surface. The silicon carbide substrate includes screw dislocations and pits having a maximum diameter of 1 ?m or more and 10 ?m or less in a direction parallel to the first main surface. When the screw dislocations and the pits are observed in the first main surface, a percentage obtained by dividing a number of the pits by a number of the screw dislocations is 1% or less. A concentration of magnesium in the first main surface is less than 1×1011 atoms/cm2.Type: GrantFiled: November 10, 2020Date of Patent: February 27, 2024Assignee: Sumitomo Electric Industries, Ltd.Inventors: Kyoko Okita, Tsubasa Honke, Shunsaku Ueta
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Publication number: 20230357957Abstract: A silicon carbide substrate has a first main surface and a second main surface opposite to the first main surface. The silicon carbide substrate includes screw dislocations and pits having a maximum diameter of 1 ?m or more and 10 ?m or less in a direction parallel to the first main surface. When the screw dislocations and the pits are observed in the first main surface, a percentage obtained by dividing a number of the pits by a number of the screw dislocations is 1% or less. A concentration of magnesium in the first main surface is less than 1×1011 atoms/cm2.Type: ApplicationFiled: November 10, 2020Publication date: November 9, 2023Inventors: Kyoko OKITA, Tsubasa HONKE, Shunsaku UETA
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Patent number: 11781246Abstract: In a case where a detector is positioned in a [11-20] direction, and where a first measurement region including a center of a main surface is irradiated with an X ray in a direction within ±15° relative to a [?1-120] direction, a ratio of a maximum intensity of a first intensity profile is more than or equal to 1500. In a case where the detector is positioned in a direction parallel to a [?1100] direction, and where the first measurement region is irradiated with an X ray in a direction within ±6° relative to a [1-100] direction, a ratio of a maximum intensity of a second intensity profile is more than or equal to 1500. An absolute value of a difference between maximum value and minimum value of energy at which the first intensity profile indicates a maximum value is less than or equal to 0.06 keV.Type: GrantFiled: November 23, 2022Date of Patent: October 10, 2023Assignee: Sumitomo Electric Industries, Ltd.Inventors: Kyoko Okita, Takashi Sakurada, Eiryo Takasuka, Shunsaku Ueta, Sho Sasaki, Naoki Kaji, Hidehiko Mishima, Hirokazu Eguchi
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Publication number: 20230081506Abstract: In a case where a detector is positioned in a [11-20] direction, and where a first measurement region including a center of a main surface is irradiated with an X ray in a direction within ±15° relative to a [?1-120] direction, a ratio of a maximum intensity of a first intensity profile is more than or equal to 1500. In a case where the detector is positioned in a direction parallel to a [?1100] direction, and where the first measurement region is irradiated with an X ray in a direction within ±6° relative to a [1-100] direction, a ratio of a maximum intensity of a second intensity profile is more than or equal to 1500. An absolute value of a difference between maximum value and minimum value of energy at which the first intensity profile indicates a maximum value is less than or equal to 0.06 keV.Type: ApplicationFiled: November 23, 2022Publication date: March 16, 2023Applicant: Sumitomo Electric Industries, Ltd.Inventors: Kyoko OKITA, Takashi SAKURADA, Eiryo TAKASUKA, Shunsaku UETA, Sho SASAKI, Naoki KAJI, Hidehiko MISHIMA, Hirokazu EGUCHI
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Patent number: 11535953Abstract: In a case where a detector is positioned in a [11-20] direction, and where a first measurement region including a center of a main surface is irradiated with an X ray in a direction within ±15° relative to a [?1-120] direction, a ratio of a maximum intensity of a first intensity profile is more than or equal to 1500. In a case where the detector is positioned in a direction parallel to a [?1100] direction, and where the first measurement region is irradiated with an X ray in a direction within ±6° relative to a [1-100] direction, a ratio of a maximum intensity of a second intensity profile is more than or equal to 1500. An absolute value of a difference between maximum value and minimum value of energy at which the first intensity profile indicates a maximum value is less than or equal to 0.06 keV.Type: GrantFiled: January 30, 2017Date of Patent: December 27, 2022Assignee: Sumitomo Electric Industries, Ltd.Inventors: Kyoko Okita, Takashi Sakurada, Eiryo Takasuka, Shunsaku Ueta, Sho Sasaki, Naoki Kaji, Hidehiko Mishima, Hirokazu Eguchi
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Publication number: 20220403550Abstract: A ratio obtained by dividing a number of pits by a number of screw dislocations is equal to or smaller than 1%. The first main surface has a surface roughness equal to or smaller than 0.15 nm. An absolute value of a difference between the first wave number and the second wave number is equal to or smaller than 0.2 cm?1, and an absolute value of a difference between the first full width at half maximum and the second full width at half maximum is equal to or smaller than 0.25 cm?1.Type: ApplicationFiled: November 12, 2020Publication date: December 22, 2022Inventors: Kyoko OKITA, Tsubasa HONKE, Shunsaku UETA
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Publication number: 20210054529Abstract: In a case where a detector is positioned in a [11-20] direction, and where a first measurement region including a center of a main surface is irradiated with an X ray in a direction within ±15° relative to a [?1-120] direction, a ratio of a maximum intensity of a first intensity profile is more than or equal to 1500. In a case where the detector is positioned in a direction parallel to a [?1100] direction, and where the first measurement region is irradiated with an X ray in a direction within ±6° relative to a [1-100] direction, a ratio of a maximum intensity of a second intensity profile is more than or equal to 1500. An absolute value of a difference between maximum value and minimum value of energy at which the first intensity profile indicates a maximum value is less than or equal to 0.06 keV.Type: ApplicationFiled: January 30, 2017Publication date: February 25, 2021Applicant: Sumitomo Electric Industries, Ltd.Inventors: Kyoko OKITA, Takashi SAKURADA, Eiryo TAKASUKA, Shunsaku UETA, Sho SASAKI, Naoki KAJI, Hidehiko MISHIMA, Hirokazu EGUCHI
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Patent number: 10361273Abstract: A silicon carbide substrate whose majority carrier density is 1×1017 cm?3 or greater is such that a standard deviation of minority carrier lifetime as obtained by ?-PCD analysis is 0.7 ns or less in an area other than an area within a distance of 5 mm from an outer perimeter of a main surface.Type: GrantFiled: October 12, 2016Date of Patent: July 23, 2019Assignee: SUMITOMO ELECTRIC INDUSTRIES, LTD.Inventors: Naoki Kaji, Shunsaku Ueta, Tsutomu Hori, Shin Harada
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Patent number: 10319821Abstract: A silicon carbide substrate includes a carbon-surface-side principal surface and a silicon-surface-side principal surface. The silicon carbide substrate has a diameter of 100 mm or greater and a thickness of 300 ?m or greater. An off angle of the carbon-surface-side principal surface and the silicon-surface-side principal surface relative to a {0001} plane is smaller than or equal to 4°. A nitrogen concentration in the carbon-surface-side principal surface is higher than a nitrogen concentration in the silicon-surface-side principal surface, and a difference in Raman peak shift between the carbon-surface-side principal surface and the silicon-surface-side principal surface is smaller than or equal to 0.2 cm?1.Type: GrantFiled: July 21, 2016Date of Patent: June 11, 2019Assignee: SUMITOMO ELECTRIC INDUSTRIES, LTD.Inventors: Shunsaku Ueta, Kyoko Okita, Shin Harada
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Patent number: 10184191Abstract: Provided is a method for manufacturing a silicon carbide single crystal capable of easily separating a silicon carbide single crystal from a pedestal. The method includes the step of fixing a seed substrate to a pedestal with a stress buffer layer being interposed therebetween, the step of growing a silicon carbide single crystal on the seed substrate, the step of separating the silicon carbide single crystal from the pedestal at the stress buffer layer, and the step of removing a residue of the stress buffer layer adhering to the silicon carbide single crystal subjected to the step of separating.Type: GrantFiled: November 21, 2014Date of Patent: January 22, 2019Assignee: SUMITOMO ELECTRIC INDUSTRIES, LTD.Inventors: Tsutomu Hori, Shunsaku Ueta, Akira Matsushima
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Publication number: 20180254323Abstract: A silicon carbide substrate includes a carbon-surface-side principal surface and a silicon-surface-side principal surface. The silicon carbide substrate has a diameter of 100 mm or greater and a thickness of 300 ?m or greater. An off angle of the carbon-surface-side principal surface and the silicon-surface-side principal surface relative to a {0001} plane is smaller than or equal to 4°. A nitrogen concentration in the carbon-surface-side principal surface is higher than a nitrogen concentration in the silicon-surface-side principal surface, and a difference in Raman peak shift between the carbon-surface-side principal surface and the silicon-surface-side principal surface is smaller than or equal to 0.2 cm?1.Type: ApplicationFiled: July 21, 2016Publication date: September 6, 2018Inventors: Shunsaku UETA, Kyoko OKITA, Shin HARADA
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Publication number: 20180254324Abstract: A silicon carbide substrate whose majority carrier density is 1×1017 cm?3 or greater is such that a standard deviation of minority carrier lifetime as obtained by ?-PCD analysis is 0.7 ns or less in an area other than an area within a distance of 5 mm from an outer perimeter of a main surface.Type: ApplicationFiled: October 12, 2016Publication date: September 6, 2018Inventors: Naoki KAJI, Shunsaku UETA, Tsutomu HORI, Shin HARADA
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Patent number: 9777401Abstract: A method for producing a single crystal includes a step of placing a source material powder and a seed crystal within a crucible; and a step of growing a single crystal on the seed crystal. The crucible includes a peripheral wall part and a bottom part and a lid part that are connected to the peripheral wall part to close the openings of the peripheral wall part. In the step of growing the single crystal on the seed crystal, the crucible is disposed on a spacer so as to form a space starting directly below an outer surface of the bottom part, and the peripheral wall part and an auxiliary heating member that is placed so as to face the outer surface of the bottom part with the space therebetween are heated by induction heating to sublime the source material powder to cause recrystallization on the seed crystal.Type: GrantFiled: August 5, 2015Date of Patent: October 3, 2017Assignee: SUMITOMO ELECTRIC INDUSTRIES, LTD.Inventors: Shunsaku Ueta, Tsutomu Hori, Akira Matsushima
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Patent number: 9777400Abstract: A method for producing a single crystal includes a step of placing a source material powder and a seed crystal within a crucible, and a step of growing a single crystal on the seed crystal. The crucible includes a peripheral wall part and a bottom part and a lid part that are connected to the peripheral wall part to close the openings of the peripheral wall part, the lid part having a holder that holds the seed crystal. The bottom part has a connection region connected to the peripheral wall part and a thick region that is thicker than the connection region and that surrounds a central axis passing through a center of gravity of orthogonal projection of the bottom part, the orthogonal projection being formed on a plane perpendicular to a growth direction of the single crystal, the central axis extending in the growth direction of the single crystal.Type: GrantFiled: July 24, 2015Date of Patent: October 3, 2017Assignee: SUMITOMO ELECTRIC INDUSTRIES, LTD.Inventors: Shunsaku Ueta, Tsutomu Hori, Akira Matsushima
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Publication number: 20170152609Abstract: 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.Type: ApplicationFiled: February 14, 2017Publication date: June 1, 2017Inventors: Shinsuke FUJIWARA, Taro NISHIGUCHI, Tsutomu HORI, Naoki OOI, Shunsaku UETA
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Patent number: 9631296Abstract: 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.Type: GrantFiled: June 11, 2013Date of Patent: April 25, 2017Assignee: Sumitomo Electric Industries, Ltd.Inventors: Shinsuke Fujiwara, Taro Nishiguchi, Tsutomu Hori, Naoki Ooi, Shunsaku Ueta
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Publication number: 20160340796Abstract: Provided is a method for manufacturing a silicon carbide single crystal capable of easily separating a silicon carbide single crystal from a pedestal. The method includes the step of fixing a seed substrate to a pedestal with a stress buffer layer being interposed therebetween, the step of growing a silicon carbide single crystal on the seed substrate, the step of separating the silicon carbide single crystal from the pedestal at the stress buffer layer, and the step of removing a residue of the stress buffer layer adhering to the silicon carbide single crystal subjected to the step of separating.Type: ApplicationFiled: November 21, 2014Publication date: November 24, 2016Inventors: Tsutomu HORI, Shunsaku UETA, Akira MATSUSHIMA
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Publication number: 20160040317Abstract: A method for producing a single crystal includes a step of placing a source material powder and a seed crystal within a crucible; and a step of growing a single crystal on the seed crystal. The crucible includes a peripheral wall part and a bottom part and a lid part that are connected to the peripheral wall part to close the openings of the peripheral wall part. In the step of growing the single crystal on the seed crystal, the crucible is disposed on a spacer so as to form a space starting directly below an outer surface of the bottom part, and the peripheral wall part and an auxiliary heating member that is placed so as to face the outer surface of the bottom part with the space therebetween are heated by induction heating to sublime the source material powder to cause recrystallization on the seed crystal.Type: ApplicationFiled: August 5, 2015Publication date: February 11, 2016Inventors: Shunsaku UETA, Tsutomu HORI, Akira MATSUSHIMA