Patents by Inventor Masahiro Araki
Masahiro Araki 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: 20150002219Abstract: A semiconductor device containing a terminal, a power supply voltage dropping circuit that generates a constant voltage, a switch circuit to periodically apply a constant voltage to a terminal in response to a first clock, a current-controlled oscillator circuit, and a counter, and in which the power supply voltage dropping circuit supplies a first current to the switch circuit, the current-controlled oscillator circuit generates a second clock whose frequency changes in response to the value of the first current, and the counter counts the number of second clocks within the counting time.Type: ApplicationFiled: May 27, 2014Publication date: January 1, 2015Applicant: RENESAS ELECTRONICS CORPORATIONInventor: Masahiro ARAKI
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Patent number: 8866153Abstract: Provided is a functional element which is obtained by forming a lamination film on a substrate and then dividing the substrate and the lamination film into a desired shape. The functional element has a hexagonal substrate, a lamination film formed on a C surface of the substrate, and a plurality of divided surfaces which are exposed by dividing the substrate into quadrilaterals. At least one line of division lines in the case of dividing the substrate into quadrilaterals is perpendicular to any one of equivalent directions of [1-100], [?1010], and [01-01] of the substrate from a [0001] direction of the substrate, and the divided surfaces formed by the division lines are inclined in a direction of other divided surfaces to which at least a part thereof is opposed.Type: GrantFiled: January 18, 2011Date of Patent: October 21, 2014Assignee: Sharp Kabushiki KaishaInventors: Akihiro Urata, Masahiro Araki, Takaaki Utsumi, Masahiro Shiota
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Patent number: 8647904Abstract: Provided is a method for manufacturing a nitride semiconductor device, including the steps of: forming an AlNO buffer layer containing at least aluminum, nitrogen, and oxygen on a substrate; and forming a nitride semiconductor layer on the AlNO buffer layer, wherein, in the step of forming the AlNO buffer layer, the AlNO buffer layer is formed by a reactive sputtering method using aluminum as a target in an atmosphere to and from which nitrogen gas and oxygen gas are continuously introduced and exhausted, and the atmosphere is an atmosphere in which a ratio of a flow rate of the oxygen gas to a sum of a flow rate of the nitrogen gas and the flow rate of the oxygen gas is not more than 0.5%.Type: GrantFiled: February 23, 2011Date of Patent: February 11, 2014Assignee: Sharp Kabushiki KaishaInventors: Masahiro Araki, Takaaki Utsumi, Masahiko Sakata
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Publication number: 20130277684Abstract: A nitride semiconductor structure in which a first nitride semiconductor underlying layer is provided on a substrate having a recess portion and a projection portion provided between the recess portions at a surface thereof, the first nitride semiconductor underlying layer has at least 6 first oblique facet planes surrounding the projection portion on an outer side of the projection portion, and a second nitride semiconductor underlying layer buries the first oblique facet planes, a nitride semiconductor light emitting element, a nitride semiconductor transistor element, a method of manufacturing a nitride semiconductor structure, and a method of manufacturing a nitride semiconductor element are provided.Type: ApplicationFiled: December 21, 2011Publication date: October 24, 2013Inventors: Masahiro Araki, Shinya Yoshida, Haruhisa Takiguchi, Atsushi Ogawa, Takao Kinoshita, Tohru Murata, Takeshi Funaki, Masayuki Hoteida
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Publication number: 20130161640Abstract: A nitride semiconductor device is provided that prevents development of cracks, that has nitride semiconductor thin films with uniform thicknesses and good growth surface flatness, and is thus consistent in characteristics, and that can be fabricated at a satisfactory yield. In this nitride semiconductor device, the nitride semiconductor thin films are grown on a substrate having an off-angle between a direction normal to the surface of ridges and the crystal direction <0001>. This helps either reduce or intentionally promote diffusion or movement of the atoms or molecules of a source material of the nitride semiconductor thin films through migration thereof. As a result, a nitride semiconductor growth layer with good surface flatness can be formed, and thus a nitride semiconductor device with satisfactory characteristics can be obtained.Type: ApplicationFiled: December 26, 2012Publication date: June 27, 2013Applicant: Sharp Kabushiki KaishaInventors: Eiji Yamada, Takeshi Kamikawa, Masahiro Araki
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Patent number: 8368183Abstract: A nitride semiconductor device is provided that prevents development of cracks, that has nitride semiconductor thin films with uniform thicknesses and good growth surface flatness, and is thus consistent in characteristics, and that can be fabricated at a satisfactory yield. In this nitride semiconductor device, the nitride semiconductor thin films are grown on a substrate having an off-angle between a direction normal to the surface of ridges and the crystal direction <0001>. This helps either reduce or intentionally promote diffusion or movement of the atoms or molecules of a source material of the nitride semiconductor thin films through migration thereof. As a result, a nitride semiconductor growth layer with good surface flatness can be formed, and thus a nitride semiconductor device with satisfactory characteristics can be obtained.Type: GrantFiled: November 1, 2005Date of Patent: February 5, 2013Assignee: Sharp Kabushiki KaishaInventors: Eiji Yamada, Takeshi Kamikawa, Masahiro Araki
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Patent number: 8350609Abstract: The present invention provides a semiconductor device in which an adjustable range of a resistance value of a variable resistance circuit is large. The semiconductor device has an output buffer including a plurality of sets of resistance elements and a plurality of sets of transistors, a plurality of replica circuits, and a plurality of sets of operational amplifiers, and drain currents of the plurality of sets of transistors are adjusted so that output impedances of the output buffer become predetermined values. Therefore, even in the case where the resistance values of the resistance elements largely fluctuate due to fluctuations in manufacture process and the like, the output impedances can be set to predetermined values.Type: GrantFiled: February 8, 2012Date of Patent: January 8, 2013Assignee: Renesas Electronics CorporationInventors: Masahiro Araki, Atsuhiko Ishibashi
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Publication number: 20120319162Abstract: Provided is a method for manufacturing a nitride semiconductor device, including the steps of: forming an AlNO buffer layer containing at least aluminum, nitrogen, and oxygen on a substrate; and forming a nitride semiconductor layer on the AlNO buffer layer, wherein, in the step of forming the AlNO buffer layer, the AlNO buffer layer is formed by a reactive sputtering method using aluminum as a target in an atmosphere to and from which nitrogen gas and oxygen gas are continuously introduced and exhausted, and the atmosphere is an atmosphere in which a ratio of a flow rate of the oxygen gas to a sum of a flow rate of the nitrogen gas and the flow rate of the oxygen gas is not more than 0.5%.Type: ApplicationFiled: February 23, 2011Publication date: December 20, 2012Applicant: Sharp Kabushiki KaishaInventors: Masahiro Araki, Takaaki Utsumi, Masahiko Sakata
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Publication number: 20120292642Abstract: Provided is a functional element which is obtained by forming a lamination film on a substrate and then dividing the substrate and the lamination film into a desired shape. The functional element has a hexagonal substrate, a lamination film formed on a C surface of the substrate, and a plurality of divided surfaces which are exposed by dividing the substrate into quadrilaterals. At least one line of division lines in the case of dividing the substrate into quadrilaterals is perpendicular to any one of equivalent directions of [1-100], [-1010], and [01-01] of the substrate from a [0001] direction of the substrate, and the divided surfaces formed by the division lines are inclined in a direction of other divided surfaces to which at least a part thereof is opposed.Type: ApplicationFiled: January 18, 2011Publication date: November 22, 2012Applicant: Sharp Kabushiki KaishaInventors: Akihiro Urata, Masahiro Araki, Takaaki Utsumi, Masahiro Shiota
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Patent number: 8288794Abstract: On a processed substrate having an engraved region as a depressed portion formed thereon, a nitride semiconductor thin film is laid. The sectional area occupied by the nitride semiconductor thin film filling the depressed portion is 0.8 times the sectional area of the depressed portion or less.Type: GrantFiled: June 10, 2010Date of Patent: October 16, 2012Assignee: Sharp Kabushiki KaishaInventors: Takeshi Kamikawa, Eiji Yamada, Masahiro Araki
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Publication number: 20120229197Abstract: The present invention provides a semiconductor device in which an adjustable range of a resistance value of a variable resistance circuit is large. The semiconductor device has an output buffer including a plurality of sets of resistance elements and a plurality of sets of transistors, a plurality of replica circuits, and a plurality of sets of operational amplifiers, and drain currents of the plurality of sets of transistors are adjusted so that output impedances of the output buffer become predetermined values. Therefore, even in the case where the resistance values of the resistance elements largely fluctuate due to fluctuations in manufacture process and the like, the output impedances can be set to predetermined values.Type: ApplicationFiled: February 8, 2012Publication date: September 13, 2012Inventors: Masahiro ARAKI, Atsuhiko Ishibashi
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Patent number: 8030110Abstract: A nitride semiconductor laser device uses a substrate with low defect density, contains reduced strains inside a nitride semiconductor film, and thus offers a satisfactorily long useful life. On a GaN substrate (10) with a defect density as low as 106 cm?2 or less, a stripe-shaped depressed portion (16) is formed by etching. On this substrate (10), a nitride semiconductor film (11) is grown, and a laser stripe (12) is formed off the area right above the depressed portion (16). With this structure, the laser stripe (12) is free from strains, and the semiconductor laser device offers a long useful life. Moreover, the nitride semiconductor film (11) develops reduced cracks, resulting in a greatly increased yield rate.Type: GrantFiled: December 27, 2010Date of Patent: October 4, 2011Assignee: Sharp Kabushiki KaishaInventors: Takeshi Kamikawa, Eiji Yamada, Masahiro Araki, Yoshika Kaneko
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Publication number: 20110136276Abstract: A nitride semiconductor laser device uses a substrate with low defect density, contains reduced strains inside a nitride semiconductor film, and thus offers a satisfactorily long useful life. On a GaN substrate (10) with a defect density as low as 106 cm?2 or less, a stripe-shaped depressed portion (16) is formed by etching. On this substrate (10), a nitride semiconductor film (11) is grown, and a laser stripe (12) is formed off the area right above the depressed portion (16). With this structure, the laser stripe (12) is free from strains, and the semiconductor laser device offers a long useful life. Moreover, the nitride semiconductor film (11) develops reduced cracks, resulting in a greatly increased yield rate.Type: ApplicationFiled: December 27, 2010Publication date: June 9, 2011Applicant: SHARP KABUSHIKI KAISHAInventors: Takeshi KAMIKAWA, Eiji Yamada, Masahiro Araki, Yoshika Kaneko
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Publication number: 20110062016Abstract: There is provided a method for manufacturing an aluminum-containing nitride intermediate layer, a method for manufacturing a nitride layer, and a method for manufacturing a nitride semiconductor element by using the nitride layer, in which at least one of the following conditions (i) to (iii) is employed during stacking of the aluminum-containing nitride intermediate layer by using a DC magnetron sputtering method in which a voltage is applied by means of a DC-continuous scheme. (i) The shortest distance between a center of a surface of a target and a growth surface of a substrate is set to 100 mm or more and 250 mm or less. (ii) Nitrogen gas is used as gas supplied to a DC magnetron sputtering apparatus. (iii) The target is inclined with respect to the growth surface of the substrate.Type: ApplicationFiled: August 11, 2010Publication date: March 17, 2011Applicant: Sharp Kabushiki KaishaInventors: Masahiro ARAKI, Takaaki Utsumi, Masahiko Sakata
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Patent number: 7903708Abstract: A nitride semiconductor laser device uses a substrate with low defect density, contains reduced strains inside a nitride semiconductor film, and thus offers a satisfactorily long useful life. On a GaN substrate (10) with a defect density as low as 106 cm?2 or less, a stripe-shaped depressed portion (16) is formed by etching. On this substrate (10), a nitride semiconductor film (11) is grown, and a laser stripe (12) is formed off the area right above the depressed portion (16). With this structure, the laser stripe (12) is free from strains, and the semiconductor laser device offers a long useful life. Moreover, the nitride semiconductor film (11) develops reduced cracks, resulting in a greatly increased yield rate.Type: GrantFiled: July 30, 2004Date of Patent: March 8, 2011Assignee: Sharp Kabushiki KaishaInventors: Takeshi Kamikawa, Eiji Yamada, Masahiro Araki, Yoshika Kaneko
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Publication number: 20100244046Abstract: On a processed substrate having an engraved region as a depressed portion formed thereon, a nitride semiconductor thin film is laid. The sectional area occupied by the nitride semiconductor thin film filling the depressed portion is 0.8 times the sectional area of the depressed portion or less.Type: ApplicationFiled: June 10, 2010Publication date: September 30, 2010Applicant: Sharp Kabushiki KaishaInventors: Takeshi Kamikawa, Eiji Yamada, Masahiro Araki
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Patent number: 7772611Abstract: On a processed substrate having an engraved region as a depressed portion formed thereon, a nitride semiconductor thin film is laid. The sectional area occupied by the nitride semiconductor thin film filling the depressed portion is 0.8 times the sectional area of the depressed portion or less.Type: GrantFiled: November 20, 2006Date of Patent: August 10, 2010Assignee: Sharp Kabushiki KaishaInventors: Takeshi Kamikawa, Eiji Yamada, Masahiro Araki
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Patent number: 7663158Abstract: A nitride compound semiconductor light emitting device includes: a GaN substrate having a crystal orientation which is tilted away from a <0001> direction by an angle which is equal to or greater than about 0.05° and which is equal to or less than about 2°, and a semiconductor multilayer structure formed on the GaN substrate, wherein the semiconductor multilayer structure includes: an acceptor doping layer containing a nitride compound semiconductor; and an active layer including a light emitting region.Type: GrantFiled: November 16, 2007Date of Patent: February 16, 2010Assignee: Sharp Kabushiki KaishaInventors: Yoshihiro Ueta, Takayuki Yuasa, Atsushi Ogawa, Yuhzoh Tsuda, Masahiro Araki
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Publication number: 20090141774Abstract: In a spread spectrum clock generator, a DLL circuit delays an oscillation clock signal from a VCO and outputs ten delay clock signals having different phases respectively. A selector selects any one of the ten delay clock signals, and outputs a selected clock signal. A control circuit controls a signal selection operation of the selector. A feedback frequency divider divides a frequency of the selected clock signal by a frequency division ratio N, and generates a comparison clock signal. In this manner, a phase of the comparison clock signal can be fine-tuned. Therefore, a spread spectrum clock generator capable of frequency modulation with high accuracy can be obtained.Type: ApplicationFiled: February 4, 2009Publication date: June 4, 2009Applicants: RENESAS TECHNOLOGY CORP, RENESAS LSI DESIGN CORPORATIONInventors: Masahiro ARAKI, Chieko Hayashi
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Publication number: 20080087905Abstract: A nitride compound semiconductor light emitting device includes: a GaN substrate having a crystal orientation which is tilted away from a <0001> direction by an angle which is equal to or greater than about 0.05° and which is equal to or less than about 2°, and a semiconductor multilayer structure formed on the GaN substrate, wherein the semiconductor multilayer structure includes: an acceptor doping layer containing a nitride compound semiconductor; and an active layer including a light emitting region.Type: ApplicationFiled: November 16, 2007Publication date: April 17, 2008Applicant: SHARP KABUSHIKI KAISHAInventors: Yoshihiro UETA, Takayuki YUASA, Atsushi OGAMA, Yuhzoh TSUDA, Masahiro ARAKI