Patents by Inventor Toshiyuki Oka
Toshiyuki Oka 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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Patent number: 8461606Abstract: According to one embodiment, a semiconductor light-emitting device includes an n-type semiconductor layer including a nitride semiconductor, a p-type semiconductor layer including a nitride semiconductor, a light-emitting portion and a stacked body. The light-emitting portion is provided between the n-type and p-type semiconductor layers and includes a barrier layer and a well layer. The well layer is stacked with the barrier layer. The stacked body is provided between the light-emitting portion and the n-type semiconductor layer and includes a first layer and a second layer. The second layer is stacked with the first layer. Average In composition ratio of the stacked body is higher than 0.4 times average In composition ratio of the light-emitting portion. The layer thickness tb of the barrier layer is 10 nanometers or less.Type: GrantFiled: September 3, 2010Date of Patent: June 11, 2013Assignee: Kabushiki Kaisha ToshibaInventors: Shigeya Kimura, Hajime Nago, Toshiyuki Oka, Koichi Tachibana, Toshiki Hikosaka, Shinya Nunoue
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Patent number: 8461615Abstract: According to one embodiment, a semiconductor light emitting device includes a stacked structural body, a first electrode, and a second electrode. The stacked structural body includes a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type, and a light emitting portion. The stacked structural body has a first major surface on a side of the second semiconductor layer. The first electrode is provided on the first semiconductor. The second electrode is provided on the second semiconductor layer. The first electrode includes a first pad portion and a first extending portion that extends from the first pad portion along a first extending direction. The first extending portion includes a first width-increasing portion. A width of the first width-increasing portion along a direction orthogonal to the first extending direction is increased from the first pad portion toward an end of the first extending portion.Type: GrantFiled: September 3, 2010Date of Patent: June 11, 2013Assignee: Kabushiki Kaisha ToshibaInventors: Shigeya Kimura, Taisuke Sato, Toshihide Ito, Toshiyuki Oka, Shinya Nunoue
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Patent number: 8455917Abstract: According to one embodiment, in a nitride semiconductor light emitting device, a first clad layer includes an n-type nitride semiconductor. An active layer is formed on the first clad layer, and includes an In-containing nitride semiconductor. A GaN layer is formed on the active layer. A first AlGaN layer is formed on the GaN layer, and has a first Al composition ratio. A p-type second AlGaN layer is formed on the first AlGaN layer, has a second Al composition ratio higher than the first Al composition ratio, and contains a larger amount of Mg than the GaN layer and the first AlGaN layer. A second clad layer is formed on the second AlGaN layer, and includes a p-type nitride semiconductor.Type: GrantFiled: August 30, 2011Date of Patent: June 4, 2013Assignee: Kabushiki Kaisha ToshibaInventors: Hajime Nago, Koichi Tachibana, Toshiyuki Oka, Shigeya Kimura, Shinya Nunoue
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Patent number: 8441023Abstract: According to one embodiment, in a light emitting device, a substrate is transparent to a wavelength of emitted light. A first dielectric layer is formed in a first region on the substrate, and has a refractive index smaller than a refractive index of the substrate. A second dielectric layer is formed in a second region on the substrate surrounding the first region, and has a refractive index larger than the refractive index of the substrate. A first semiconductor layer is formed on the first dielectric layer, the second dielectric layer and the substrate. A second semiconductor layer is formed on the first semiconductor layer, and includes an active layer having a PN junction.Type: GrantFiled: September 6, 2011Date of Patent: May 14, 2013Assignee: Kabushiki Kaisha ToshibaInventors: Taisuke Sato, Masanobu Ando, Hajime Nago, Koichi Tachibana, Toshiyuki Oka, Shinya Nunoue
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Patent number: 8421108Abstract: According to one embodiment, a semiconductor light emitting device includes a first semiconductor layer, a second semiconductor layer and a light emitting part. The first semiconductor layer includes an n-type semiconductor layer. The second semiconductor layer includes a p-type semiconductor layer. The light emitting part is provided between the first semiconductor layer and the second semiconductor layer, and includes a plurality of barrier layers and a well layer provided between the plurality of barrier layers. The first semiconductor layer has a first irregularity and a second irregularity. The first irregularity is provided on a first major surface of the first semiconductor layer on an opposite side to the light emitting part. The second irregularity is provided on a bottom face and a top face of the first irregularity, and has a level difference smaller than a level difference between the bottom face and the top face.Type: GrantFiled: August 12, 2011Date of Patent: April 16, 2013Assignee: Kabushiki Kaisha ToshibaInventors: Hiroshi Ono, Toshiki Hikosaka, Tomoko Morioka, Toshiyuki Oka, Shinya Nunoue
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Patent number: 8395263Abstract: According to one embodiment, a semiconductor light emitting device includes a stacked structural body, a first, a second and a third conductive layer. The stacked structural body includes first and second semiconductors and a light emitting layer provided therebetween. The second semiconductor layer is disposed between the first conductive layer and the light emitting layer. The first conductive layer is transparent. The first conductive layer has a first major surface on a side opposite to the second semiconductor layer. The second conductive layer is in contact with the first major surface. The third conductive layer is in contact with the first major surface and has a reflectance higher than a reflectance of the second conductive layer. The third conductive layer includes an extending part extending in parallel to the first major surface. At least a portion of the extending part is not covered by the second conductive layer.Type: GrantFiled: February 17, 2011Date of Patent: March 12, 2013Assignee: Kabushiki Kaisha ToshibaInventors: Taisuke Sato, Toshiyuki Oka, Koichi Tachibana, Shinya Nunoue
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Publication number: 20130059408Abstract: Certain embodiments provide a method for manufacturing a semiconductor light emitting device, including: providing a first stack film on a first substrate, the first stack film being formed by stacking a p-type nitride semiconductor layer, an active layer having a multiquantum well structure of a nitride semiconductor, and an n-type nitride semiconductor layer in this order; forming an n-electrode on an upper face of the n-type nitride semiconductor layer; and forming a concave-convex region on the upper face of the n-type nitride semiconductor layer by performing wet etching on the upper face of the n-type nitride semiconductor layer with the use of an alkaline solution, except for a region in which the n-electrode is formed.Type: ApplicationFiled: October 31, 2012Publication date: March 7, 2013Inventors: Kotaro Zaima, Toru Gotoda, Toshiyuki Oka, Shinya Nunoue
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Patent number: 8390012Abstract: A semiconductor light emitting device has a support substrate, a light emitting element, and underfill material. The light emitting element includes a nitride-based group III-V compound semiconductor layer contacted via a bump on the support substrate. The underfill material is disposed between the support substrate and the light emitting element, the underfill material comprising a rib portion disposed outside of an end face of the light emitting element to surround the end surface of the light emitting element.Type: GrantFiled: September 2, 2010Date of Patent: March 5, 2013Assignee: Kabushiki Kaisha ToshibaInventors: Toru Gotoda, Hajime Nago, Toshiyuki Oka, Kotaro Zaima, Shinya Nunoue
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Patent number: 8390007Abstract: A semiconductor light emitting device has a light emitting element, and first and second electrodes. The light emitting element has a nitride-based III-V compound semiconductor on a substrate. The first and second electrodes are disposed on both sides of the light emitting element, respectively. The light emitting element has a light emitting layer, a first conductive type semiconductor layer, and a second conductive type semiconductor layer. The first conductive type semiconductor layer is disposed between the light emitting layer and the first electrode. The second conductive type semiconductor layer is disposed between the light emitting layer and the second electrode. One surface of the first conductive type semiconductor layer contacts the first electrode and is a light extraction surface which is roughly processed so as to have two or more kinds of oblique angles.Type: GrantFiled: September 2, 2010Date of Patent: March 5, 2013Assignee: Kabushiki Kaisha ToshibaInventors: Toru Gotoda, Takahiro Sato, Toshiyuki Oka, Shinya Nunoue, Kotaro Zaima
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Publication number: 20120319161Abstract: According to one embodiment, a method is disclosed for manufacturing a semiconductor light emitting device. The method can include forming a nitride semiconductor layer including a light emitting layer on a first substrate having an unevenness, bonding the nitride layer to a second substrate, and separating the first substrate from the nitride layer by irradiating the nitride layer with light. The forming the nitride layer includes leaving a cavity in a space inside a depression of the unevenness while forming a thin film on the depression. The film includes a same material as part of the nitride layer. The separating includes causing the film to absorb part of the light so that intensity of the light applied to a portion of the nitride layer facing the depression is made lower than intensity of the light applied to a portion facing a protrusion of the unevenness.Type: ApplicationFiled: February 27, 2012Publication date: December 20, 2012Applicant: Kabushiki Kaisha ToshibaInventors: Toru GOTODA, Toshiyuki Oka, Shinya Nunoue, Kotaro Zaima, Hiroshi Ono, Hajime Nago
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Patent number: 8334153Abstract: A semiconductor light emitting device has a light emitting element, a first electrode layer, a second electrode layer, a seed electrode layer and a plated layer. The light emitting element has a nitride-based III-V compound semiconductor on a substrate. The light emitting element having a light extraction surface. The first electrode layer on the light extraction surface. The second electrode layer is provided on a surface opposite to the light extraction surface of the light emitting element. The seed electrode layer is configured to cover the entire surface of the second electrode layer. The plated layer is provided on the seed electrode layer. The light emitting element has a light emitting layer, a first conductive type semiconductor layer, and a second conductive type semiconductor layer.Type: GrantFiled: September 2, 2010Date of Patent: December 18, 2012Assignee: Kabushiki Kaisha ToshibaInventors: Toru Gotoda, Toshiyuki Oka, Shinya Nunoue, Kotaro Zaima
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Publication number: 20120299015Abstract: According to one embodiment, a nitride semiconductor device includes a substrate and a semiconductor functional layer. The substrate is a single crystal. The semiconductor functional layer is provided on a major surface of the substrate and includes a nitride semiconductor. The substrate includes a plurality of structural bodies disposed in the major surface. Each of the plurality of structural bodies is a protrusion provided on the major surface or a recess provided on the major surface. An absolute value of an angle between a nearest direction of an arrangement of the plurality of structural bodies and a nearest direction of a crystal lattice of the substrate in a plane parallel to the major surface is not less than 1 degree and not more than 10 degrees.Type: ApplicationFiled: February 27, 2012Publication date: November 29, 2012Applicant: Kabushiki Kaisha ToshibaInventors: Koichi TACHIBANA, Hisashi Yoshida, Hiroshi Ono, Hajime Nago, Yoshiyuki Harada, Toshiki Hikosaka, Maki Sugai, Toshiyuki Oka, Shinya Nunoue
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Publication number: 20120292648Abstract: According to one embodiment, a nitride semiconductor device includes a foundation layer and the functional layer. The foundation layer is formed on an amorphous layer and includes aluminum nitride. The functional layer is formed on the foundation layer and includes a nitride semiconductor.Type: ApplicationFiled: August 26, 2011Publication date: November 22, 2012Applicant: Kabushiki Kaisha ToshibaInventors: Hiroshi Ono, Tomonari Shioda, Naoharu Sugiyama, Toshiyuki Oka, Shinya Nunoue
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Publication number: 20120292631Abstract: According to one embodiment, a semiconductor light emitting device includes a stacked structure body, a first electrode, a second electrode, and a dielectric body part. The stacked structure body includes a first semiconductor layer, having a first portion and a second portion juxtaposed with the first portion, a light emitting layer provided on the second portion, a second semiconductor layer provided on the light emitting layer. The first electrode includes a contact part provided on the first portion and contacting the first layer. The second electrode includes a first part provided on the second semiconductor layer and contacting the second layer, and a second part electrically connected with the first part and including a portion overlapping with the contact part when viewed from the first layer toward the second layer. The dielectric body part is provided between the contact part and the second part.Type: ApplicationFiled: August 31, 2011Publication date: November 22, 2012Applicant: Kabushiki Kaisha ToshibaInventors: Hiroshi KATSUNO, Satoshi Mitsugi, Toshiyuki Oka, Shinya Nunoue
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Patent number: 8314437Abstract: Certain embodiments provide a method for manufacturing a semiconductor light emitting device, including: providing a first stack film on a first substrate, the first stack film being formed by stacking a p-type nitride semiconductor layer, an active layer having a multiquantum well structure of a nitride semiconductor, and an n-type nitride semiconductor layer in this order; forming an n-electrode on an upper face of the n-type nitride semiconductor layer; and forming a concave-convex region on the upper face of the n-type nitride semiconductor layer by performing wet etching on the upper face of the n-type nitride semiconductor layer with the use of an alkaline solution, except for a region in which the n-electrode is formed.Type: GrantFiled: September 2, 2010Date of Patent: November 20, 2012Assignee: Kabushiki Kaisha ToshibaInventors: Kotaro Zaima, Toru Gotoda, Toshiyuki Oka, Shinya Nunoue
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Patent number: 8242532Abstract: According to one embodiment, a semiconductor light-emitting device having high light extraction efficiency is provided. The semiconductor light-emitting device includes a light transmissive substrate; a nitride semiconductor layer of a first conduction type formed on or above a top face side of the light transmissive substrate; an active layer made of nitride semiconductor formed on a top face of the nitride semiconductor layer of the first conduction type; a nitride semiconductor layer of a second conduction type formed on a top face of the active layer; a dielectric layer formed on a bottom face of the light transmissive substrate and having a refractive index lower than that of the light transmissive substrate; and a metal layer formed on a bottom face of the dielectric layer. And an interface between the light transmissive substrate and the dielectric layer is a uneven face, and an interface between the dielectric layer and the metal layer is a flat face.Type: GrantFiled: September 1, 2010Date of Patent: August 14, 2012Assignee: Kabushiki Kaisha ToshibaInventors: Taisuke Sato, Toshiyuki Oka, Koichi Tachibana, Shinya Nunoue, Kazufumi Shiozawa, Takayoshi Fujii
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Publication number: 20120199811Abstract: Certain embodiments provide a semiconductor light emitting device including: a first metal layer; a stack film including a p-type nitride semiconductor layer, an active layer, and an n-type nitride semiconductor layer; an n-electrode; a second metal layer; and a protection film protecting an outer circumferential region of the upper face of the n-type nitride semiconductor layer, side faces of the stack film, a region of an upper face of the second metal layer other than a region in contact with the p-type nitride semiconductor layer, and a region of an upper face of the first metal layer other than a region in contact with the second metal layer. Concavities and convexities are formed in a region of the upper face of the n-type nitride semiconductor layer, the region being outside the region in which the n-electrode is provided and being outside the regions covered with the protection film.Type: ApplicationFiled: April 18, 2012Publication date: August 9, 2012Applicant: Kabushiki Kaisha ToshibaInventors: Kotaro Zaima, Toru Gotoda, Toshiyuki Oka, Shinya Nunoue
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Publication number: 20120187446Abstract: According to one embodiment, a semiconductor light emitting device includes first and second conductive layers, a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type, and a light emitting part. The second semiconductor layer is provided between the first conductive layer and the first semiconductor layer. The light emitting part is provided between the first and second semiconductor layers. The second conductive layer is in contact with the second semiconductor layer and the first conductive layer between the second semiconductor layer and the first conductive layer. The first and second conductive layers are transmittable to light emitted from the light emitting part. The first conductive layer includes a polycrystal having a first average grain diameter. The second conductive layer includes a polycrystal having a second average grain diameter of 150 nanometers or less and smaller than the first average grain diameter.Type: ApplicationFiled: August 26, 2011Publication date: July 26, 2012Applicant: Kabushiki Kaisha ToshibaInventors: Toshihide ITO, Toshiyuki Oka, Shinya Nunoue
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Publication number: 20120138985Abstract: According to one embodiment, a semiconductor light emitting device includes a first semiconductor layer, a second semiconductor layer and a light emitting part. The first semiconductor layer includes an n-type semiconductor layer. The second semiconductor layer includes a p-type semiconductor layer. The light emitting part is provided between the first semiconductor layer and the second semiconductor layer, and includes a plurality of barrier layers and a well layer provided between the plurality of barrier layers. The first semiconductor layer has a first irregularity and a second irregularity. The first irregularity is provided on a first major surface of the first semiconductor layer on an opposite side to the light emitting part. The second irregularity is provided on a bottom face and a top face of the first irregularity, and has a level difference smaller than a level difference between the bottom face and the top face.Type: ApplicationFiled: August 12, 2011Publication date: June 7, 2012Applicant: Kabushiki Kaisha ToshibaInventors: Hiroshi ONO, Toshiki HIKOSAKA, Tomoko MORIOKA, Toshiyuki OKA, Shinya NUNOUE
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Patent number: 8188510Abstract: According to one embodiment, a semiconductor light-emitting device having high light extraction efficiency is provided. The semiconductor light-emitting device includes a light transmissive substrate; a nitride semiconductor layer of a first conduction type formed on or above a top face side of the light transmissive substrate; an active layer made of nitride semiconductor formed on a top face of the nitride semiconductor layer of the first conduction type; a nitride semiconductor layer of a second conduction type formed on a top face of the active layer; a dielectric layer formed on a bottom face of the light transmissive substrate and having a refractive index lower than that of the light transmissive substrate; and a metal layer formed on a bottom face of the dielectric layer. And an interface between the light transmissive substrate and the dielectric layer is a uneven face, and an interface between the dielectric layer and the metal layer is a flat face.Type: GrantFiled: September 1, 2010Date of Patent: May 29, 2012Assignee: Kabushiki Kaisha ToshibaInventors: Taisuke Sato, Toshiyuki Oka, Koichi Tachibana, Shinya Nunoue, Kazufumi Shiozawa, Takayoshi Fujii