Patents by Inventor Koichi Tachibana
Koichi Tachibana 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: 20120132940Abstract: According to one embodiment, an optical semiconductor device includes an n-type semiconductor layer, a p-type semiconductor layer, and a functional part. The functional part is provided between the n-type semiconductor layer and the p-type semiconductor layers. The functional part includes a plurality of active layers stacked in a direction from the n-type semiconductor layer toward the p-type semiconductor layer. At least two of the active layers include a multilayer stacked body, an n-side barrier layer, a well layer and a p-side barrier layer. The multilayer stacked body includes a plurality of thick film layers and a plurality of thin film layers alternately stacked in the direction. The n-side barrier layer is provided between the multilayer stacked body and the p-type layer. The well layer is provided between the n-side barrier layer and the p-type layer. The p-side barrier layer is provided between the well layer and the p-type layer.Type: ApplicationFiled: August 22, 2011Publication date: May 31, 2012Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Tomonari Shioda, Hisashi Yoshida, Koichi Tachibana, Naoharu Sugiyama, Shinya Nunoue
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Publication number: 20120132943Abstract: According to one embodiment, a semiconductor light emitting device includes an n-type semiconductor layer, an electrode, a p-type semiconductor layer and a light emitting layer. The p-type semiconductor layer is provided between the n-type semiconductor layer and the electrode and includes a p-side contact layer contacting the electrode. The light emitting layer is provided between the n-type and the p-type semiconductor layers. The p-side contact layer includes a flat part having a plane perpendicular to a first direction from the n-type semiconductor layer toward the p-type semiconductor layer and multiple protruding parts protruding from the flat part toward the electrode. A height of the multiple protruding parts along the first direction is smaller than one-fourth of a dominant wavelength of light emitted from the light emitting layer. A density of the multiple protruding parts in the plane is 5×107/cm2 or more and 2×108/cm2 or less.Type: ApplicationFiled: August 5, 2011Publication date: May 31, 2012Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Toshiki HIKOSAKA, Hajime Nago, Koichi Tachibana, Toshihide Ito, 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
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Publication number: 20120061713Abstract: According to one embodiment, a semiconductor light emitting device includes: a stacked structure body, first and second electrodes, and a pad layer. The body includes first semiconductor layer of a first conductivity type, a light emitting layer, and a second semiconductor layer of second conductivity type. The first semiconductor layer has first and second portions. The light emitting layer is provided on the second portion. The second semiconductor layer is provided on the light emitting layer. The first electrode is provided on the first portion. The second electrode is provided on the second semiconductor layer and is transmittable to light emitted from the light emitting layer. The pad layer is connected to the second electrode. A transmittance of the pad layer is lower than that of the second electrode. A sheet resistance of the second electrode increases continuously along a direction from the pad layer toward the first electrode.Type: ApplicationFiled: August 31, 2011Publication date: March 15, 2012Applicant: Kabushiki Kaisha ToshibaInventors: Koichi Tachibana, Shigeya Kimura, Toshiki Hikosaka, Taisuke Sato, Toshiyuki Oka, Shinya Nunoue
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Publication number: 20120056220Abstract: 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: ApplicationFiled: September 6, 2011Publication date: March 8, 2012Applicant: Kabushiki Kaisha ToshibaInventors: Taisuke SATO, Masanobu Ando, Hajime Nago, Koichi Tachibana, Toshiyuki Oka, Shinya Nunoue
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Publication number: 20120056157Abstract: According to one embodiment, a semiconductor light emitting device includes an n-type layer, a p-type layer, and a light emitting unit provided between the n-type layer and the p-type layer and including barrier layers and well layers. At least one of the barrier layers includes first and second portion layers. The first portion layer is disposed on a side of the n-type layer. The second portion layer is disposed on a side of the p-type layer, and contains n-type impurity with a concentration higher than that in the first portion layer. At least one of the well layers includes third and fourth portion layers. The third portion layer is disposed on a side of the n-type layer. The fourth portion layer is disposed on a side of the p-type layer, and contains n-type impurity with a concentration higher than that in the third portion layer.Type: ApplicationFiled: August 31, 2011Publication date: March 8, 2012Applicant: Kabushiki Kaisha ToshibaInventors: Toshiki Hikosaka, Koichi Tachibana, Hajime Nago, Shinya Nunoue
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Publication number: 20120049157Abstract: 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: ApplicationFiled: August 30, 2011Publication date: March 1, 2012Inventors: Hajime NAGO, Koichi Tachibana, Toshiyuki Oka, Shigeya Kimura, Shinya Nunoue
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Publication number: 20120049155Abstract: According to one embodiment, a semiconductor light emitting device includes a first semiconductor layer, a second semiconductor layer, a light emitting part, and a multilayered structural body. The light emitting part is provided between the first and second semiconductor layers and includes barrier layers and well layers alternately stacked. The multilayered structural body is provided between the first semiconductor layer and the light emitting part and includes high energy layers and low energy layers alternately stacked. An average In composition ratio on a side of the second semiconductor is higher than that on a side of the first semiconductor in the multilayered structural body. An average In composition ratio on a side of the second semiconductor is higher than that on a side of the first semiconductor in the light emitting part.Type: ApplicationFiled: February 18, 2011Publication date: March 1, 2012Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Koichi TACHIBANA, Hajime Nago, Toshiki Hikosaka, Shigeya Kimura, Shinya Nunoue
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Publication number: 20120032209Abstract: According to one embodiment, a semiconductor light emitting device includes: semiconductor layers; a multilayered structural body; and a light emitting portion. The multilayered structural body is provided between the semiconductor layers, and includes a first layer and a second layer including In. The light emitting portion is in contact with the multilayered structural body between the multilayered structural body and p-type semiconductor layer, and includes barrier layers and a well layer including In with an In composition ratio among group III elements higher than an In composition ratio among group III elements in the second layer. An average lattice constant of the multilayered structural body is larger than that of the n-type semiconductor layer. Difference between the average lattice constant of the multilayered structural body and that of the light emitting portion is less than difference between that of the multilayered structural body and that of the n-type semiconductor layer.Type: ApplicationFiled: February 23, 2011Publication date: February 9, 2012Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Tomonari SHIODA, Toshiki Hikosaka, Yoshiyuki Harada, Koichi Tachibana, Shinya Nunoue
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Publication number: 20120032213Abstract: 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: ApplicationFiled: February 17, 2011Publication date: February 9, 2012Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Taisuke SATO, Toshiyuki Oka, Koichi Tachibana, Shinya Nunoue
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Publication number: 20120012814Abstract: According to one embodiment, a semiconductor light emitting device includes an n-type semiconductor layer, a p-type semiconductor layer, and a light emitting part provided therebetween. The light emitting part includes a plurality of light emitting layers. Each of the light emitting layers includes a well layer region and a non-well layer region which is juxtaposed with the well layer region in a plane perpendicular to a first direction from the n-type semiconductor layer towards the p-type semiconductor layer. Each of the well layer regions has a common An In composition ratio. Each of the well layer regions includes a portion having a width in a direction perpendicular to the first direction of 50 nanometers or more.Type: ApplicationFiled: February 25, 2011Publication date: January 19, 2012Applicant: Kabushiki Kaisha ToshibaInventors: Yoshiyuki HARADA, Toshiki Hikosaka, Tomonari Shioda, Koichi Tachibana, Hajime Nago, Shinya Nunoue
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Patent number: 8093083Abstract: In one embodiment, a method is disclosed for manufacturing a semiconductor light emitting device. The device includes a crystal layer including a nitride semiconductor. The crystal layer contains In and Ga atoms. The method can include forming the crystal layer by supplying a source gas including a first molecule including Ga atoms and a second molecule including In atoms onto a base body. The crystal layer has a ratio xs of a number of the In atoms to a total of the In atoms and the Ga atoms being not less than 0.2 and not more than 0.4. A vapor phase supply ratio xv of In is a ratio of a second partial pressure to a total of first and second partial pressures. The first and second partial pressures are pressure of the first and second molecules and degradation species of the first and second molecules on the source gas, respectively. (1?1/xv)/(1?1/xs) is less than 0.1.Type: GrantFiled: February 17, 2011Date of Patent: January 10, 2012Assignee: Kabushiki Kaisha ToshibaInventors: Toshiki Hikosaka, Tomonari Shioda, Yoshiyuki Harada, Naoharu Sugiyama, Koichi Tachibana, Shinya Nunoue
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Patent number: 8035524Abstract: In an RFID tag mounting package mounted with an RFID tag and a manufacturing method thereof, in order to have sufficient communication performance without spoiling the design property of the package to which a conductive film is applied, a package is obtained by assembling a structural material in which a metallic film is formed on a base material made of paper or the like. In the package, a slot is provided in the metallic film of a folded portion, in a spot where portions (the folded portion and an external packaging portion) of the structural material overlap each other. An inlet operates as an RFID tag, includes an antenna and an IC chip connected to the antenna, and is mounted on the inner surface of the folded portion in conformity with the position of the slot.Type: GrantFiled: February 28, 2008Date of Patent: October 11, 2011Assignee: Hitachi, Ltd.Inventors: Isao Sakama, Koichi Tachibana
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Publication number: 20110215370Abstract: 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: ApplicationFiled: September 1, 2010Publication date: September 8, 2011Applicant: Kabushiki Kaisha ToshibaInventors: Taisuke Sato, Toshiyuki Oka, Koichi Tachibana, Shinya Nunoue, Kazufumi Shiozawa, Takayoshi Fujii
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Publication number: 20110215291Abstract: According to one embodiment, a semiconductor light-emitting device using an ITON layer for a transparent conductor and realizing low drive voltage, high luminance efficiency, and uniformed light emission intensity distribution is provided. The semiconductor light-emitting device includes: a substrate; an n-type semiconductor layer formed on the substrate; an active layer formed on the n-type semiconductor layer; a p-type semiconductor layer formed on the active layer and whose uppermost part is a p-type GaN layer; an ITON (Indium Tin Oxynitride) layer formed on the p-type GaN layer; an ITO (Indium Tin Oxide) layer formed on the ITON layer; a first metal electrode formed on a part on the ITO layer; and a second metal electrode formed in contact with the n-type semiconductor layer.Type: ApplicationFiled: September 1, 2010Publication date: September 8, 2011Applicant: Kabushiki Kaisha ToshibaInventors: Toshihide Ito, Koichi Tachibana, Shinya Nunoue
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Publication number: 20110215351Abstract: 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: ApplicationFiled: September 3, 2010Publication date: September 8, 2011Applicant: Kabushiki Kaisha ToshibaInventors: Shigeya Kimura, Hajime Nago, Toshiyuki Oka, Koichi Tachibana, Toshiki Hikosaka, Shinya Nunoue
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Publication number: 20110204411Abstract: According to one embodiment, a crystal growth method is disclosed for growing a crystal of a nitride semiconductor on a major surface of a substrate. The major surface is provided with asperities. The method can include depositing a buffer layer on the major surface at a rate of not more than 0.1 micrometers per hour. The buffer layer includes GaxAl1-xN (0.1?x<0.5) and has a thickness of not smaller than 20 nanometers and not larger than 50 nanometers. In addition, the method can include growing the crystal including a nitride semiconductor on the buffer layer at a temperature higher than a temperature of the substrate in the depositing the buffer layer.Type: ApplicationFiled: September 3, 2010Publication date: August 25, 2011Applicant: Kabushiki Kaisha ToshibaInventors: Hajime NAGO, Koichi TACHIBANA, Toshiki HIKOSAKA, Shinya NUNOUE
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Patent number: 8004004Abstract: The present invention provides a semiconductor light emitting element with excellent color rendering properties, a method for manufacturing the semiconductor light emitting element, and a light emitting device. The semiconductor light emitting element includes: a semiconductor substrate that has a convex portion having a tilted surface as an upper face, and a concave portion formed on either side of the convex portion, the concave portion having a smaller width than the convex portion, a bottom face of the concave portion being located in a deeper position than the upper face of the convex portion; and a light emitting layer that is made of a nitride-based semiconductor and is formed on the semiconductor substrate so as to cover at least the convex portion.Type: GrantFiled: November 29, 2010Date of Patent: August 23, 2011Assignee: Kabushiki Kaisha ToshibaInventors: Hajime Nago, Koichi Tachibana, Kotaro Zaima, Shinji Saito, Shinya Nunoue, Toshiyuki Oka
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Publication number: 20110198561Abstract: According to one embodiment, a semiconductor light emitting device includes an n-type semiconductor layer, a p-type semiconductor layer, a light emitting portion, a first layer, a second layer, and an intermediate layer. The semiconductor layers include nitride semiconductor. The light emitting portion is provided between the n-type semiconductor layer and the p-type semiconductor layer and includes a quantum well layer. The first layer is provided between the light emitting portion and the p-type semiconductor layer and includes AlX1Ga1-x1N having first Al composition ratio x1. The second layer is provided between the first layer and the p-type semiconductor layer and includes Alx2Ga1-x2N having second Al composition ratio x2 higher than the first Al composition ratio x1. The intermediate layer is provided between the first layer and the light emitting portion and has a thickness not smaller than 3 nanometers and not larger than 8 nanometers and includes Inz1Ga1-z1N (0?z1<1).Type: ApplicationFiled: September 2, 2010Publication date: August 18, 2011Applicant: Kabushiki Kaisha ToshibaInventors: Koichi TACHIBANA, Hajime Nago, Toshiki Hikosaka, Shigeya Kimura, Shinya Nunoue
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Publication number: 20110198583Abstract: According to one embodiment, a semiconductor light emitting device includes n-type and p-type semiconductor layers, a light emitting portion, a multilayered structural body, and an n-side intermediate layer. The light emitting portion is provided between the semiconductor layers. The light emitting portion includes barrier layers containing GaN, and a well layer provided between the barrier layers. The well layer contains Inx1Ga1-x1N. The body is provided between the n-type semiconductor layer and the light emitting portion. The body includes: first layers containing GaN, and a second layer provided between the first layers. The second layer contains Inx2Ga1-x2N. Second In composition ratio x2 is not less than 0.6 times of first In composition ratio x1 and is lower than the first In composition x1. The intermediate layer is provided between the body and the light emitting portion and includes a third layer containing Aly1Ga1-y1N (0<y1?0.01).Type: ApplicationFiled: September 1, 2010Publication date: August 18, 2011Applicant: Kabushiki Kaisha ToshibaInventors: Hajime NAGO, Koichi Tachibana, Toshiki Hikosaka, Shigeya Kimura, Shinya Nunoue