Patents by Inventor Kunihiko Tasai

Kunihiko Tasai 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).

  • Publication number: 20240030332
    Abstract: A semiconductor device including: a channel layer; a spacer layer; an intermediate layer; and a barrier layer. The channel layer includes a first nitride semiconductor. The spacer layer includes a second nitride semiconductor having a larger band gap than a band gap of the first nitride semiconductor. The spacer layer is provided on the channel layer. The intermediate layer includes Alx1Iny1Ga(1-x1-y1)N(0<x1<1, 0<y1<1, and 0<x1+y1<1). The intermediate layer is provided on the spacer layer. The barrier layer includes Alx2In(1-x2)N(0<x2<1). The barrier layer is provided on the intermediate layer.
    Type: Application
    Filed: August 5, 2021
    Publication date: January 25, 2024
    Inventors: KUNIHIKO TASAI, TAKAHIRO KOYAMA, NORIYUKI FUTAGAWA, SEI FUKUSHIMA, YUYA KANITANI
  • Publication number: 20220190555
    Abstract: A compound semiconductor layer stack includes: a first layer 11 being formed on a base 14 and including an island-shaped Alx1Iny1Ga(1-x1-y1)N; a second layer 12 being formed on the first layer 11 and including Alx2Iny2Ga(1-x2-y2)N; and a third layer 13 being formed on an entire surface including a top of the second layer 12, the third layer 13 including Alx3Ga(1-x3)N (provided that the following hold true: 0?x1<1; 0?x2<1; 0?x3<1; 0?y1<1; and 0<y2<1), and the third layer 13 has a top surface 13A that is flat.
    Type: Application
    Filed: March 31, 2020
    Publication date: June 16, 2022
    Inventors: KUNIHIKO TASAI, HIROSHI NAKAJIMA, HIDEKAZU KAWANISHI, KATSUNORI YANASHIMA
  • Publication number: 20220006265
    Abstract: A nitride semiconductor laser device of one embodiment of the present disclosure includes a single-crystal substrate, a base layer, a sheet-shaped structure, a light emitting layer, and a resonator mirror. The single-crystal substrate extends in one direction. The base layer is provided on the single-crystal substrate and includes a nitride semiconductor. The sheet-shaped structure is provided on the base layer to stand in a direction perpendicular to the base layer. The sheet-shaped structure has an area of a side surface that is greater than an area of an upper surface. The side surface extends in a longitudinal direction of the single-crystal substrate. The sheet-shaped structure includes a nitride semiconductor. The light emitting layer is provided at least on the side surface of the sheet-shaped structure. The light emitting layer includes a nitride semiconductor. The resonator mirror is provided by a pair of end surfaces of the sheet-shaped structure that oppose each other in the longitudinal direction.
    Type: Application
    Filed: October 25, 2019
    Publication date: January 6, 2022
    Inventors: TAKASHI TANGE, KUNIHIKO TASAI, KOTA TOKUDA
  • Publication number: 20210320224
    Abstract: A light-emitting device according to one embodiment of the present disclosure includes: a substrate; a first quantum well layer including Alx2Inx1Ga(1-x1-x2)N (0<x1<1, 0?x2<1) and including a light-emitting region; a barrier layer provided between the substrate and the first quantum well layer; and a second quantum well layer including Aly2Iny1Ga(1-y1-y2)N (0<y1<1, 0?y2<1) and having a thickness of less than 4.0 monolayers and provided between the substrate and the barrier layer, at a position 8 nm or more and less than 50 nm away from the first quantum well layer.
    Type: Application
    Filed: August 2, 2019
    Publication date: October 14, 2021
    Inventors: Kunihiko TASAI, Hidekazu KAWANISHI, Katsunori YANASHIMA
  • Publication number: 20210159362
    Abstract: A light emitting device according to an embodiment of the present disclosure includes: a first layer including Alx2Inx1Ga(1-x1-x2) N (0<x1<1, 0?x2<1); a second layer that is provided on the first layer and includes Aly2Iny1Ga(1-y1-y2) N (0<y1<1, 0?y2<1) that is lattice relaxed with respect to the first layer; and a third layer that is provided on the second layer, includes Alz2Inz1Ga(1-z1-z2) N (0<z1<1, 0?z2<1) that is lattice relaxed with respect to the second layer, and includes an active layer. A lattice constant aGAN of GaN in an in-plane direction, a lattice constant al of the first layer in an in-plane direction, a lattice constant a2 of the second layer in an in-plane direction, and a lattice constant a3 of the third layer in an in-plane direction have a relationship of aGAN<a2<a1, a3.
    Type: Application
    Filed: July 1, 2019
    Publication date: May 27, 2021
    Inventors: Kunihiko TASAI, Hiroshi NAKAJIMA, Hidekazu KAWANISHI, Katsunori YANASHIMA
  • Publication number: 20210135050
    Abstract: A template substrate including: a first layer that includes Alx2Inx1Ga(1-x1-x2)N (0<x1<1, 0?x2<1) and has a lattice constant a1 in an in-plane direction greater than a lattice constant of GaN in the in-plane direction, the first layer being lattice-relaxed; a second layer that is stacked on the first layer to be lattice-matched to the first layer and includes AlyGa(1-y)N (0?y<1); and a third layer that is provided opposed to the first layer with the second layer being interposed therebetween, the third layer being lattice-matched to the second layer and including Alz2Inz1Ga(0-z1-z2)N (0<z1<1, 0?z2<1).
    Type: Application
    Filed: June 19, 2018
    Publication date: May 6, 2021
    Inventors: Kunihiko TASAI, Hiroshi NAKAJIMA, Hidekazu KAWANISHI, Katsunori YANASHIMA
  • Patent number: 10236663
    Abstract: A semiconductor optical device includes a laminated structure constituted of a first compound semiconductor layer of an n type, an active layer, and a second compound semiconductor layer of a p type, the active layer including at least 3 barrier layers and well layers interposed among the barrier layers, and the semiconductor optical device satisfying Egp-BR>Egn-BR>EgWell when a bandgap energy of the barrier layer adjacent to the second compound semiconductor layer is represented by Egp-BR, a bandgap energy of the barrier layer between the well layers is represented by EgWell, and a bandgap energy of the barrier layer adjacent to the first compound semiconductor layer is represented by Egn-BR.
    Type: Grant
    Filed: March 11, 2016
    Date of Patent: March 19, 2019
    Assignee: SONY CORPORATION
    Inventors: Katsunori Yanashima, Kunihiko Tasai
  • Publication number: 20180138662
    Abstract: A semiconductor optical device includes a laminated structure constituted of a first compound semiconductor layer of an n type, an active layer, and a second compound semiconductor layer of a p type, the active layer including at least 3 barrier layers and well layers interposed among the barrier layers, and the semiconductor optical device satisfying Egp-BR>Egn-BR>EgWell when a bandgap energy of the barrier layer adjacent to the second compound semiconductor layer is represented by Egp-BR, a bandgap energy of the barrier layer between the well layers is represented by EgWell, and a bandgap energy of the barrier layer adjacent to the first compound semiconductor layer is represented by Egn-BR.
    Type: Application
    Filed: March 11, 2016
    Publication date: May 17, 2018
    Applicant: SONY CORPORATION
    Inventors: KATSUNORI YANASHIMA, KUNIHIKO TASAI
  • Patent number: 9871349
    Abstract: There is provided a light-emitting element including a laminated structure including a first compound semiconductor layer having a first conductivity type, a second compound semiconductor layer having a second conductivity type different than the first conductivity type, and a third compound semiconductor layer formed between the first and second compound semiconductor layers and including an active layer. A second end surface of the second compound semiconductor layer and a third end surface of the third compound semiconductor layer are formed at respective second and third angles theta2 and theta3 relative to a virtual vertical direction of the laminated structure and satisfy the following relationship: “absolute value of theta3 is equal to or greater than 0 degree and smaller than absolute value of theta2”.
    Type: Grant
    Filed: November 10, 2014
    Date of Patent: January 16, 2018
    Assignee: SONY CORPORATION
    Inventors: Kunihiko Tasai, Eiji Nakayama, Yuusuke Nakayama, Shigetaka Tomiya
  • Publication number: 20160268776
    Abstract: There is provided a light-emitting element including a laminated structure including a first compound semiconductor layer having a first conductivity type, a second compound semiconductor layer having a second conductivity type different than the first conductivity type, and a third compound semiconductor layer formed between the first and second compound semiconductor layers and including an active layer. A second end surface of the second compound semiconductor layer and a third end surface of the third compound semiconductor layer are formed at respective second and third angles theta2 and theta3 relative to a virtual vertical direction of the laminated structure and satisfy the following relationship: “absolute value of theta3 is equal to or greater than 0 degree and smaller than absolute value of theta2”.
    Type: Application
    Filed: November 10, 2014
    Publication date: September 15, 2016
    Inventors: KUNIHIKO TASAI, EIJI NAKAYAMA, YUUSUKE NAKAYAMA, SHIGETAKA TOMIYA
  • Patent number: 9231375
    Abstract: A semiconductor device includes: a semiconductor substrate made of a hexagonal Group III nitride semiconductor and having a semi-polar plane; and an epitaxial layer formed on the semi-polar plane of the semiconductor substrate and including a first cladding layer of a first conductive type, a second cladding layer of a second conductive type, and a light-emitting layer formed between the first cladding layer and the second cladding layer, the first cladding layer being made of Inx1Aly1Ga1-x1-y1N, where x1>0 and y1>0, the second cladding layer being made of Inx2Aly2Ga1-x2-y2N, where0?x2?about 0.02 and about 0.03?y2?about 0.07.
    Type: Grant
    Filed: February 12, 2013
    Date of Patent: January 5, 2016
    Assignees: Sony Corporation, Sumitomo Electric Industries, Ltd.
    Inventors: Kunihiko Tasai, Hiroshi Nakajima, Noriyuki Futagawa, Katsunori Yanashima, Yohei Enya, Tetsuya Kumano, Takashi Kyono
  • Patent number: 8923354
    Abstract: A nitride semiconductor laser comprises a conductive support base having a primary surface of gallium nitride based semiconductor, an active layer on the primary surface, and a p-type cladding region on the primary surface. The primary surface is tilted to a reference plane perpendicular to a reference axis extending in the c-axis direction of the gallium nitride based semiconductor. The p-type cladding region comprises a first p-type group III nitride semiconductor layer of an AlGaN layer anisotropically-strained, and a second p-type group III nitride semiconductor layer of material different from the AlGaN layer. The first p-type group III nitride semiconductor layer is provided between the second p-type group III nitride semiconductor layer and the active layer. The AlGaN layer has the largest bandgap in the p-type cladding region. The second p-type group III nitride semiconductor layer has a resistivity lower than the first p-type group III nitride semiconductor layer.
    Type: Grant
    Filed: October 4, 2012
    Date of Patent: December 30, 2014
    Inventors: Takashi Kyono, Yohei Enya, Takamichi Sumitomo, Yusuke Yoshizumi, Masaki Ueno, Katsunori Yanashima, Kunihiko Tasai, Hiroshi Nakajima
  • Patent number: 8731016
    Abstract: A nitride semiconductor light-emitting device has a semiconductor ridge, and includes a first inner-layer between an active layer and an n-type cladding and a second inner-semiconductor layer between the active layer and a p-type cladding. The first inner-layer, active layer and second inner-layer constitute a core-region. The n-type cladding, core-region and p-type cladding constitute a waveguide-structure. The active layer and the first inner-layer constitute a first heterojunction inclined at an angle greater than zero with respect to a reference plane of the c-plane of the nitride semiconductor of the n-type cladding. Piezoelectric polarization of the well layer is oriented in a direction from the p-type cladding toward the n-type cladding. The second inner-layer and InGaN well layer constitute a second heterojunction. A distance between the ridge bottom and the second heterojunction is 200 nm or less. The ridge includes a third heterojunction between the second inner-layer and the p-type cladding.
    Type: Grant
    Filed: October 23, 2012
    Date of Patent: May 20, 2014
    Assignees: Sumitomo Electric Industries, Ltd., Sony Corporation
    Inventors: Takashi Kyono, Yohei Enya, Masaki Ueno, Katsunori Yanashima, Kunihiko Tasai, Hiroshi Nakajima, Noriyuki Futagawa
  • Patent number: 8718110
    Abstract: A nitride semiconductor laser includes an electrically conductive support substrate with a primary surface of a gallium nitride based semiconductor, an active layer provided above the primary surface, and a p-type cladding region provided above the primary surface. The primary surface is inclined relative to a reference plane perpendicular to a reference axis extending in a direction of the c-axis of the gallium nitride based semiconductor. The p-type cladding region includes first and second p-type Group III nitride semiconductor layers. The first p-type semiconductor layer comprises an InAlGaN layer including built-in anisotropic strain. The second p-type semiconductor layer comprises semiconductor different from material of the InAlGaN layer. The first nitride semiconductor layer is provided between the second p-type semiconductor layer and the active layer. The second p-type semiconductor layer has a resistivity lower than that of the first p-type semiconductor layer.
    Type: Grant
    Filed: February 6, 2012
    Date of Patent: May 6, 2014
    Assignees: Sumitomo Electric Industries, Ltd., Sony Corporation
    Inventors: Takashi Kyono, Yohei Enya, Takamichi Sumitomo, Yusuke Yoshizumi, Masaki Ueno, Katsunori Yanashima, Kunihiko Tasai, Hiroshi Nakajima
  • Patent number: 8477818
    Abstract: A gallium nitride-based semiconductor laser device with reduced threshold current. The gallium nitride-based semiconductor laser device is provided with an n-type cladding layer, an n-side light guide layer, an active layer, a p-side light guide layer, and a p-type cladding layer. The n-side light guide layer and the p-side light guide layer both contain indium. Each of indium compositions of the n-side light guide layer and the p-side light guide layer is not less than 2% and not more than 6%. A film thickness of the n-type cladding layer is in the range of not less than 65% and not more than 85% of a total of the film thickness of the n-type cladding layer and a film thickness of the p-type cladding layer.
    Type: Grant
    Filed: March 27, 2012
    Date of Patent: July 2, 2013
    Assignees: Sumitomo Electric Industries, Ltd., Sony Corporation
    Inventors: Tetsuya Kumano, Masaki Ueno, Takashi Kyono, Yohei Enya, Katsunori Yanashima, Kunihiko Tasai, Hiroshi Nakajima
  • Publication number: 20130009202
    Abstract: A group-III nitride semiconductor device includes a light emitting layer emitting light of a wavelength in the range of 480 to 600 nm; a first contact layer over the light emitting layer; a second contact layer in direct contact with the first contact layer; and a metal electrode in direct contact with the second contact layer. The first and second contact layers comprise a p-type gallium nitride-based semiconductor. The p-type dopant concentration of the first contact layer is lower than that of the second contact layer. The light emitting layer comprises a gallium nitride-based semiconductor. The interface between the first and second contact layers tilts at an angle of not less than 50 degrees and smaller than 130 degrees from a plane orthogonal to a reference axis extending along the c-axis. The second contact layer has a thickness within the range of 1 to 50 nm.
    Type: Application
    Filed: June 29, 2012
    Publication date: January 10, 2013
    Applicants: SONY CORPORATION, SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Yohei ENYA, Yusuke YOSHIZUMI, Takashi KYONO, Takamichi SUMITOMO, Masaki UENO, Katsunori YANASHIMA, Kunihiko TASAI, Hiroshi NAKAJIMA
  • Publication number: 20130003769
    Abstract: A gallium nitride-based semiconductor laser device with reduced threshold current. The gallium nitride-based semiconductor laser device is provided with an n-type cladding layer, an n-side light guide layer, an active layer, a p-side light guide layer, and a p-type cladding layer. The n-side light guide layer and the p-side light guide layer both contain indium. Each of indium compositions of the n-side light guide layer and the p-side light guide layer is not less than 2% and not more than 6%. A film thickness of the n-type cladding layer is in the range of not less than 65% and not more than 85% of a total of the film thickness of the n-type cladding layer and a film thickness of the p-type cladding layer 23.
    Type: Application
    Filed: March 27, 2012
    Publication date: January 3, 2013
    Applicants: SONY CORPORATION, SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Tetsuya Kumano, Masaki Ueno, Takashi Kyono, Yohei Enya, Katsunori Yanashima, Kunihiko Tasai, Hiroshi Nakajima
  • Publication number: 20120327967
    Abstract: A nitride semiconductor laser device includes a p-type cladding layer, an active layer and an n-type cladding layer. The p-type cladding layer and the n-type cladding layer comprise indium and aluminum as group-III constituent. The n-type cladding layer, active layer and p-type cladding layer are arranged along the normal of a semi-polar semiconductor surface of a substrate. This surface tilts toward the m-axis of the hexagonal nitride by an angle of 63 degrees or more and smaller than 80 degrees from a plane orthogonal to a reference axis extending along the c-axis thereof. The active layer generates light having a peak wavelength in the range of 480 to 600 nm. The refractive indices of the n-type cladding layer and p-type cladding layer are smaller than that of GaN. The n-type cladding layer has a thickness of 2 ?m or more while the p-type cladding layer has a thickness of 500 nm or more.
    Type: Application
    Filed: May 24, 2012
    Publication date: December 27, 2012
    Applicants: SONY CORPORATION, SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Yohei ENYA, Yusuke YOSHIZUMI, Takashi KYONO, Takamichi SUMITOMO, Masaki UENO, Katsunori YANASHIMA, Kunihiko TASAI, Hiroshi NAKAJIMA
  • Publication number: 20120269222
    Abstract: A nitride semiconductor laser includes an electrically conductive support substrate with a primary surface of a gallium nitride based semiconductor, an active layer provided above the primary surface, and a p-type cladding region provided above the primary surface. The primary surface is inclined relative to a reference plane perpendicular to a reference axis extending in a direction of the c-axis of the gallium nitride based semiconductor. The p-type cladding region includes first and second p-type Group III nitride semiconductor layers. The first p-type semiconductor layer comprises an InAlGaN layer including built-in anisotropic strain. The second p-type semiconductor layer comprises semiconductor different from material of the InAlGaN layer. The first nitride semiconductor layer is provided between the second p-type semiconductor layer and the active layer. The second p-type semiconductor layer has a resistivity lower than that of the first p-type semiconductor layer.
    Type: Application
    Filed: February 6, 2012
    Publication date: October 25, 2012
    Applicants: SONY CORPORATION, SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Takashi KYONO, Yohei ENYA, Takamichi SUMITOMO, Yusuke YOSHIZUMI, Masaki UENO, Katsunori YANASHIMA, Kunihiko TASAI, Hiroshi NAKAJIMA
  • Patent number: 8050305
    Abstract: A semiconductor device having high reliability, a long lifetime and superior light emitting characteristics by applying a novel material to a p-type cladding layer is provided. A semiconductor device includes a p-type semiconductor layer on an InP substrate, in which the p-type semiconductor layer has a laminate structure formed by alternately laminating a first semiconductor layer mainly including Bex1Mgx2Znx3Te (0<x1<1, 0?x2<1, 0<x3<1, x1+x2+x3=1) and a second semiconductor layer mainly including Bex4Mgx5Znx6Te (0<x4<1, 0<x5<1, 0?x6<1, x4+x5+x6=1).
    Type: Grant
    Filed: June 3, 2008
    Date of Patent: November 1, 2011
    Assignees: Sony Corporation, Hitachi, Ltd., Sophia School Corporation
    Inventors: Katsumi Kishino, Ichiro Nomura, Koshi Tamamura, Kunihiko Tasai, Tsunenori Asatsuma, Hitoshi Nakamura, Sumiko Fujisaki, Takeshi Kikawa