Patents by Inventor Yukio Shakuda
Yukio Shakuda 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: 20090278143Abstract: A plurality of transistors are formed on a substrate in a plurality of columns. Each transistor has a first conductivity type region and second conductivity type regions provided on both sides thereof in a column direction, and has an active layer on the side of each second conductivity type region closer to the substrate. Between two columns adjacent to each other, the second conductivity type region on a first side in the column direction of each transistor arranged on a first column, the second conductivity type region on a second side in the column direction of the transistor adjacent to this transistor on the first side in the column direction and the first conductivity type region of each transistor arranged on a second column are electrically connected by a first wire.Type: ApplicationFiled: April 3, 2007Publication date: November 12, 2009Applicant: ROHM CO., LTD.Inventor: Yukio Shakuda
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Patent number: 7616672Abstract: A semiconductor light emitting device of double hetero junction includes an active layer and clad layers. The clad layers include an n-type layer and p-type layer. The clad layers sandwich the active layer. A band gap energy of the clad layers is larger than that of the active layer. The band gap energy of the n-type clad layer is smaller than of the p-type clad layer.Type: GrantFiled: June 7, 2005Date of Patent: November 10, 2009Assignee: Rohm Co., Ltd.Inventor: Yukio Shakuda
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Publication number: 20090269867Abstract: The present invention provides a method of manufacturing a nitride semiconductor capable of improving the crystallinity and the surface state of the nitride semiconductor crystal formed on top of a high-temperature AlN buffer layer. An AlN buffer layer is formed on top of a growth substrate, and then nitride semiconductor crystals are grown on top of the AlN buffer layer. In a stage of manufacturing the nitride semiconductor, the crystal of the AlN buffer layer is grown at a high temperature of 900° C. or higher. In addition, an Al-source material of the AlN buffer layer is started to be supplied first to a reaction chamber and continues to be supplied without interruption, and then a N-source material is supplied intermittently.Type: ApplicationFiled: August 23, 2007Publication date: October 29, 2009Applicant: ROHM CO., LTDInventor: Yukio Shakuda
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Publication number: 20090256170Abstract: A semiconductor light emitter (A) includes an n-type semiconductor layer (2), a p-type semiconductor layer (4), and an active layer (3) between these two layers (2, 4). The light emitter (A) further includes an n-side electrode (5) on the n-type layer (2) and a p-side electrode (6) on the p-type layer (4). An insulating layer (7) covers the n-type and p-type layers (2),(4), while also partially covering the n-side and p-side electrodes (5),(6), leaving part of the electrodes (5, 6) exposed. The n-side electrode (5) has a first Al layer (51) formed on the n-type layer (2) and a second Ni, W, Zr or Pt layer (52) formed on the first layer (51). The p-side electrode (6) has a first Au layer (61) formed on the p-type layer (4), and a second Ni, W, Zr or Pt layer (62) formed on the first layer (61).Type: ApplicationFiled: July 3, 2007Publication date: October 15, 2009Applicant: ROHM CO., LTD.Inventor: Yukio Shakuda
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Patent number: 7592633Abstract: A semiconductor lamination portion is formed on a substrate by laminating semiconductor layers so as to form a light emitting layer, and a plurality of light emitting units are formed by separating the semiconductor lamination portion electrically into a plurality of units. Each of the units has a pair of electric connecting portions which are connected to a pair of conductivity type layers and they are connected to each other with a wiring film. Each of the plurality of the light emitting units is separated electrically by dividing the conductivity type layers of the semiconductor lamination portion with at least twofold separating grooves (a first separating groove and a second separating groove). As a consequence, a semiconductor light emitting device with a high luminance and being formed in a monolithic type having a plurality of light emitting units can be obtained to solve a problem of a short-circuit occurrence between the light emitting units while keeping high reliability of wiring or the like.Type: GrantFiled: May 16, 2006Date of Patent: September 22, 2009Assignee: Rohm Co., Ltd.Inventor: Yukio Shakuda
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Publication number: 20090166668Abstract: There is provided a nitride semiconductor light emitting device having high internal quantum efficiency by accelerating recombination radiation while employing a multiple quantum well structure in which each of well layers has a relatively large thickness. The nitride semiconductor light emitting device is provided with a nitride semiconductor lamination portion (6) provided on a substrate (1). The nitride semiconductor lamination portion (6) includes at least an active layer (4) in which a light emitting portion is formed. And the active layer is constituted with a multiple quantum well structure formed by laminating well layers (7) made of InxGa1-xN (0<x?1), and barrier layers (8) made of AlyInzGa1-y-zN (0?y<1, 0?z<1, 0?y+z<1, z<x) alternately.Type: ApplicationFiled: November 28, 2006Publication date: July 2, 2009Applicant: ROHM CO., LTD.Inventor: Yukio Shakuda
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Publication number: 20090160361Abstract: A light emitting element group includes a plurality of light emitting element units connected in series. A first current limiting circuit is arranged in series with the light emitting element group, and limits a first drive current flowing from one end to the other end of the light emitting element group. A second current limiting circuit is arranged in parallel to the first current limiting circuit, and limits a second drive current flowing in an opposite direction to the first drive current in the light emitting element group. The light emitting element units are configured to include a first light emitting element and a second light emitting element; an anode of the first light emitting element and a cathode of the second light emitting element are connected, and an anode of the second light emitting element and a cathode of the first light emitting element are connected.Type: ApplicationFiled: November 15, 2006Publication date: June 25, 2009Applicant: ROHM CO., LTD.Inventor: Yukio Shakuda
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Publication number: 20090146187Abstract: An undoped GaN layer, a silicon film, an n type GaN layer, an MQW active layer and a p type GaN layer are stacked sequentially in this order on an AlN buffer layer formed on a sapphire substrate. In this manner, the silicon film is formed in the mid-section of the GaN layers. The AlN buffer layer is crystal-grown at a high temperature. The construction is formed such that a reflectivity of light from a crystal-growing surface is once decreased in a crystal-growing process of the n type GaN layer formed on the silicon film, and the reflectivity of light is increased from the crystal-growing surface in a crystal-growing process of a nitride semiconductor layer to be formed on the n type GaN layer.Type: ApplicationFiled: December 5, 2008Publication date: June 11, 2009Applicant: ROHM CO., LTD.Inventor: Yukio Shakuda
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Publication number: 20090127539Abstract: As an example of a nitride semiconductor light emitting device, on a sapphire substrate, a GaN buffer layer, an n-type GaN contact layer, an MQW active layer, and a p-type GaN contact layer are sequentially stacked, and a partial region from the p-type GaN contact layer to the middle of the n-type GaN contact layer is mesa-etched so as to form an n electrode. Meanwhile, a p electrode is provided on the p-type GaN contact layer, and, in addition to the p electrode, multiple ridge parts are formed by crystal growth so as to be scattered. By providing the multiple ridge parts, device characteristics can be improved without causing damage on the GaN-based semiconductor layer.Type: ApplicationFiled: November 5, 2008Publication date: May 21, 2009Applicant: ROHM CO., LTD.Inventor: Yukio Shakuda
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Publication number: 20090121240Abstract: There is provided a nitride semiconductor device with low leakage current and high efficiency in which, while a zinc oxide based compound such as MgxZn1-xO (0?x?0.5) is used for a substrate, crystallinity of nitride semiconductor grown thereon is improved and film separation or cracks are prevented. The nitride semiconductor device is formed by laminating nitride semiconductor layers on a substrate (1) made of a zinc oxide based compound such as MgxZn1-xO (0?x?0.5). The nitride semiconductor layers include a first nitride semiconductor layer (2) made of AlyGa1-yN (0.05?y?0.2) which is provided in contact with the substrate (1), and nitride semiconductor layers (3) to (5) laminated on the first nitride semiconductor layer (2) so as to form a semiconductor element.Type: ApplicationFiled: October 19, 2006Publication date: May 14, 2009Applicant: ROHM CO., LTDInventors: Yukio Shakuda, Masayuki Sonobe, Norikazu Ito
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Publication number: 20090101925Abstract: A light emitting element including: a growth substrate, which has, as a main plane, a plane on which cleavage directions are orthogonal to each other; a first nitride semiconductor layer formed on the main plane of the growth substrate; an active layer formed on the first nitride semiconductor layer; and a second nitride semiconductor layer formed on the active layer. An angle formed on the main plane by the side of the growth substrate and one of the cleavage directions is ranging approximately from 30° to 60°.Type: ApplicationFiled: March 1, 2007Publication date: April 23, 2009Applicant: Rohm Co., LTD.Inventor: Yukio Shakuda
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Patent number: 7501662Abstract: A semiconductor light emitting element array includes a substrate made of SiC and having a first surface and a second surface opposite to the first surface. The array also includes a plurality of semiconductor light emitting elements supported by the first surface of the substrate. Each of the light emitting elements includes an n-type semiconductor layer, an active layer, and a p-type semiconductor layer. The second surface of the substrate serves as a light emitting surface, from which light produced by the light emitting elements is emitted out.Type: GrantFiled: May 9, 2007Date of Patent: March 10, 2009Assignee: Rohm Co., Ltd.Inventors: Masayuki Sonobe, Yukio Shakuda
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Publication number: 20090026972Abstract: To provide a light emitting unit and a lighting apparatus capable of handling different voltages. A lighting apparatus 1 includes a switching controller 2 and a light emitting unit 3. The light emitting unit 3 includes two light emitting arrays 21a and 21b and three voltage input terminals 22a to 22c. The switching controller 2 switches connection of the voltage input terminals 22a to 22c according to a supplied voltage of a power supply to connect the light emitting arrays 21a and 21b in parallel or series. A specified voltage is thus applied to the light emitting arrays 21a and 21b.Type: ApplicationFiled: December 20, 2006Publication date: January 29, 2009Applicant: ROHM CO., LTD.Inventor: Yukio Shakuda
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Publication number: 20080099767Abstract: A GaN related compound semiconductor element includes: a channel layer made of a GaN related compound semiconductor; and a source layer and a drain layer, which are disposed in a manner of sandwiching the channel layer. The source layer includes two adjacent ridge portions which are formed by selective growth. A source electrode is formed over the surface, sandwiched by the ridge portions, of the channel layer, and the surfaces of the respective two adjacent ridge portions. The selective-growth mask formed between the two ridge portions is removed by wet etching. In addition, as another embodiment, a gate electrode is formed in a manner that the direction of the longer dimension of the gate electrode is aligned with the m plane of the channel layer. Moreover, as still another embodiment, the channel layer has a multilayer structure in which a GaN layer doped with no impurity is used as an intermediate layer.Type: ApplicationFiled: September 13, 2007Publication date: May 1, 2008Applicant: ROHM CO., LTD.Inventor: Yukio Shakuda
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Publication number: 20080090387Abstract: A method of making a semiconductor element is provided. The method includes a step of forming a GaN layer doped with a p-type impurity on a substrate and a step of subjecting the GaN layer to activation process to form a p-type semiconductor layer. The activation process is performed with the GaN layer immersed in molten Ga. Preferably, the molten Ga contains a p-type impurity.Type: ApplicationFiled: September 14, 2007Publication date: April 17, 2008Applicant: ROHM CO., LTD.Inventor: Yukio Shakuda
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Publication number: 20080067539Abstract: A semiconductor light emitting element includes a substrate with upper and lower surfaces, a first nitride semiconductor layer on the upper surface of the substrate, a second nitride semiconductor layer arranged farther from the substrate than the first nitride semiconductor layer is, an active layer between the first and second nitride semiconductor layers, and a metal electrode on the second nitride semiconductor layer. As viewed in the thickness direction of the substrate, in which the upper and the lower surfaces are spaced from each other, an active layer area provided with the active layer is smaller than a semiconductor layer area provided with the second nitride semiconductor layer. An electrode area provided with the metal electrode overlaps with at least part of a residual area which is equal to the semiconductor layer area except the active layer area.Type: ApplicationFiled: August 29, 2007Publication date: March 20, 2008Applicant: ROHM CO., LTD.Inventor: Yukio Shakuda
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Publication number: 20070284598Abstract: There is provided a highly reliable semiconductor light emitting device in which disconnection of wires does not occur in case that a semiconductor light emitting device capable of being used in place of incandescent lamps or fluorescent lamps is formed in a monolithic type by forming a plurality of light emitting units on one substrate. A plurality of light emitting units (1) are formed by electrically separating a semiconductor lamination portion (17) which is so formed on a substrate (11) as to form a light emitting layer, and the light emitting units (1) are respectively connected in series and/or parallel by wiring films (3). For obtaining the light emitting units (1) from the semiconductor lamination portion a separation groove (17a) and an insulation film (21) deposited in the separation groove (17a) are formed in the semiconductor lamination portion (17).Type: ApplicationFiled: September 1, 2005Publication date: December 13, 2007Inventors: Yukio Shakuda, Toshio Nishida, Masayuki Sonobe
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Publication number: 20070278502Abstract: There is provided a semiconductor light emitting device which can prevent flickering in illumination due to an alternative current drive, and sensing incongruity at a time of turning off a switch, by providing anti-flickering means in itself, when it is assembled in an illumination device without any extra parts therein. A plurality of light emitting units (1) are formed, by forming a semiconductor lamination portion (17) by laminating semiconductor layers on a substrate (11) so as to form a light emitting layer, by electrically separating the semiconductor lamination portion (17) into a plurality of units, and by providing a pair of electrodes (19) and (20). The light emitting units (1) are respectively connected in series and/or parallel with a wiring film (3).Type: ApplicationFiled: September 12, 2005Publication date: December 6, 2007Applicant: ROHM CO., LTD.Inventors: Yukio Shakuda, Toshio Nishida, Masayuki Sonobe
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Publication number: 20070262323Abstract: A semiconductor light emitting element array includes a substrate made of SiC and having a first surface and a second surface opposite to the first surface. The array also includes a plurality of semiconductor light emitting elements supported by the first surface of the substrate. Each of the light emitting elements includes an n-type semiconductor layer, an active layer, and a p-type semiconductor layer. The second surface of the substrate serves as a light emitting surface, from which light produced by the light emitting elements is emitted out.Type: ApplicationFiled: May 9, 2007Publication date: November 15, 2007Applicant: ROHM CO., LTD.Inventors: Masayuki Sonobe, Yukio Shakuda
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Publication number: 20070257268Abstract: There is provided a highly reliable semiconductor light emitting device even in using for street lamps or traffic signals, which can be used in place of electric lamps or fluorescent lamps by protecting from surges such as static electricity or the like. A plurality of light emitting units (1) are formed, by forming a semiconductor lamination portion by laminating semiconductor layers on a substrate so as to form a light emitting layer, by electrically separating the semiconductor lamination portion into a plurality, and by providing a pair of electrodes (19) and (20). The light emitting units (1) are respectively connected in series and/or in parallel with wiring films (3). An inductor (8) absorbing surges is connected, in series, to the plurality of light emitting units (1) connected in series between electrode pads (4a) and (4b) connected to an external power source. For an example, the inductor (8) is formed by arranging the plurality of light emitting units (1) in a whirl shape.Type: ApplicationFiled: September 12, 2005Publication date: November 8, 2007Inventors: Yukio Shakuda, Toshio Nishida, Masayuki Sonobe