Patents by Inventor Toshiyuki Takizawa

Toshiyuki Takizawa 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: 20230326624
    Abstract: An oxide insulator film contains a first metal oxide and a second metal oxide. An electrical conductivity of the second metal oxide is lower than an electrical conductivity of the first metal oxide. The oxide insulator film includes particles of the first metal oxide which are dispersed in a matrix including the second metal oxide.
    Type: Application
    Filed: September 2, 2021
    Publication date: October 12, 2023
    Inventors: Takashi SASAKI, Seiji TAGUCHI, Yoshihisa NAGASAKI, Toshiyuki TAKIZAWA
  • Publication number: 20230167271
    Abstract: An additive for an organic conductor includes a naphthalene ring, at least two sulfonic acid groups bonded to the naphthalene ring, and at least one carboxy group bonded to the naphthalene ring. In the case where the number of the sulfonic acid groups is two, when the sulfonic acid groups are respectively referred to as a first sulfonic acid group and a second sulfonic acid group, and a carbon atom of the naphthalene ring bonded to the first sulfonic acid group and a carbon atom of the naphthalene ring bonded to the second sulfonic acid group are respectively referred to as a first carbon atom and a second carbon atom, the number n of carbon atoms present between the first carbon atom and the second carbon atom is three or less.
    Type: Application
    Filed: April 19, 2021
    Publication date: June 1, 2023
    Inventors: Keisuke HAYASHI, Nobuyuki MATSUZAWA, Toshiyuki TAKIZAWA, Hiroyuki MAESHIMA
  • Publication number: 20220367748
    Abstract: A nitride semiconductor structure includes a Group III nitride semiconductor portion and a Group II-IV nitride semiconductor portion. The Group III nitride semiconductor portion is single crystalline. The Group III nitride semiconductor portion has a predetermined crystallographic plane. The Group II-IV nitride semiconductor portion is provided on the predetermined crystallographic plane of the Group III nitride semiconductor portion. The Group II-IV nitride semiconductor portion is single crystalline. The Group II-IV nitride semiconductor portion contains a Group II element and a Group IV element. The Group II-IV nitride semiconductor portion forms a heterojunction with the Group III nitride semiconductor portion. The predetermined crystallographic plane is a crystallographic plane other than a (0001) plane.
    Type: Application
    Filed: October 8, 2020
    Publication date: November 17, 2022
    Inventor: Toshiyuki TAKIZAWA
  • Patent number: 9006778
    Abstract: A nitride semiconductor light emitting device includes: an uneven substrate having an uneven structure in which recesses are formed; a first nitride semiconductor layer of a first conductive type formed on the uneven structure; a first light emitting layer formed on the first nitride semiconductor layer; and a second nitride semiconductor layer of a second conductive type formed on the light emitting layer, wherein each protrusion has a bottom made of a material or composition having a thermal expansion coefficient larger than the thermal expansion coefficient of the material or composition of the first nitride semiconductor layer.
    Type: Grant
    Filed: November 13, 2012
    Date of Patent: April 14, 2015
    Assignee: Panasonic Intellectual Property Mangement Co., Ltd.
    Inventors: Shinichiro Nozaki, Toshiyuki Takizawa, Kazuhiko Yamanaka
  • Publication number: 20140376205
    Abstract: A phosphor according to the present disclosure is obtained by adding a rare earth element to a host material having boron, nitrogen, and oxygen as main components, and a composition formula is represented by B(l)O(m)N(n):Z. Here, B, O, N, and Z indicate boron, oxygen, nitrogen, and the rare earth element, respectively. Moreover, each of l, m, and n indicates element content.
    Type: Application
    Filed: September 9, 2014
    Publication date: December 25, 2014
    Inventor: Toshiyuki TAKIZAWA
  • Patent number: 8816366
    Abstract: An object of the present invention is to provide a nitride semiconductor device which shifts a luminescence wavelength toward a longer wavelength side without decreasing luminescence efficiency, and the nitride semiconductor device according to an implementation of the present invention includes: a GaN layer having a (0001) plane and a plane other than the (0001) plane; and an InGaN layer which contacts the GaN layer and includes indium, and the InGaN layer has a higher indium composition ratio in a portion that contacts the plane other than the (0001) plane than in a portion that contacts the (0001) plane.
    Type: Grant
    Filed: May 11, 2011
    Date of Patent: August 26, 2014
    Assignee: Panasonic Corporation
    Inventors: Toshiyuki Takizawa, Tetsuzo Ueda
  • Patent number: 8748939
    Abstract: The transistor includes an underlying layer 301 formed on a substrate 300, and a first layer (including an operation layer 302) made of a nitride semiconductor formed on the underlying layer 301. The underlying layer 301 is a multilayered structure including a plurality of stacked nitride semiconductor layers. The underlying layer 301 includes a transition-metal-containing layer containing at least one of cobalt, nickel, ruthenium, osmium, rhodium, or iridium which is a transition metal.
    Type: Grant
    Filed: August 6, 2012
    Date of Patent: June 10, 2014
    Assignee: Panasonic Corporation
    Inventors: Toshiyuki Takizawa, Tetsuzo Ueda
  • Patent number: 8716753
    Abstract: The nitride semiconductor material according to the present invention includes a group III nitride semiconductor and a group IV nitride formed on the group III nitride semiconductor, where an interface between the group III nitride semiconductor and the group IV nitride has a regular atomic arrangement. Moreover, an arrangement of nitrogen atoms of the group IV nitride in the interface and an arrangement of group III atoms of the group III nitride semiconductor in the interface may be substantially identical.
    Type: Grant
    Filed: December 8, 2010
    Date of Patent: May 6, 2014
    Assignee: Panasonic Corporation
    Inventors: Toshiyuki Takizawa, Tetsuzo Ueda
  • Publication number: 20120299059
    Abstract: The transistor includes an underlying layer 301 formed on a substrate 300, and a first layer (including an operation layer 302) made of a nitride semiconductor formed on the underlying layer 301. The underlying layer 301 is a multilayered structure including a plurality of stacked nitride semiconductor layers. The underlying layer 301 includes a transition-metal-containing layer containing at least one of cobalt, nickel, ruthenium, osmium, rhodium, or iridium which is a transition metal.
    Type: Application
    Filed: August 6, 2012
    Publication date: November 29, 2012
    Applicant: Panasonic Corporation
    Inventors: Toshiyuki TAKIZAWA, Tetsuzo UEDA
  • Patent number: 8283677
    Abstract: A nitride semiconductor light-emitting device includes a substrate (101) made of silicon, a mask film (102) made of silicon oxide, formed on a principal surface of the substrate (101), and having at least one opening (102a), a seed layer (104) made of GaN selectively formed on the substrate (101) in the opening (102a), an LEG layer (105) formed on a side surface of the seed layer (104), and an n-type GaN layer (106), an active layer (107), and a p-type GaN layer (108) which are formed on the LEG layer (105). The LEG layer (105) is formed by crystal growth using an organic nitrogen material as a nitrogen source.
    Type: Grant
    Filed: February 2, 2009
    Date of Patent: October 9, 2012
    Assignee: Panasonic Corporation
    Inventors: Toshiyuki Takizawa, Tetsuzo Ueda, Manabu Usuda
  • Publication number: 20110211607
    Abstract: An object of the present invention is to provide a nitride semiconductor device which shifts a luminescence wavelength toward a longer wavelength side without decreasing luminescence efficiency, and the nitride semiconductor device according to an implementation of the present invention includes: a GaN layer having a (0001) plane and a plane other than the (0001) plane; and an InGaN layer which contacts the GaN layer and includes indium, and the InGaN layer has a higher indium composition ratio in a portion that contacts the plane other than the (0001) plane than in a portion that contacts the (0001) plane.
    Type: Application
    Filed: May 11, 2011
    Publication date: September 1, 2011
    Applicant: Panasonic Corporation
    Inventors: Toshiyuki Takizawa, Tetsuzo Ueda
  • Publication number: 20110073910
    Abstract: The nitride semiconductor material according to the present invention includes a group III nitride semiconductor and a group IV nitride formed on the group III nitride semiconductor, where an interface between the group III nitride semiconductor and the group IV nitride has a regular atomic arrangement. Moreover, an arrangement of nitrogen atoms of the group IV nitride in the interface and an arrangement of group III atoms of the group III nitride semiconductor in the interface may be substantially identical.
    Type: Application
    Filed: December 8, 2010
    Publication date: March 31, 2011
    Applicant: Panasonic Corporation
    Inventors: Toshiyuki Takizawa, Tetsuzo Ueda
  • Patent number: 7915646
    Abstract: The nitride semiconductor material according to the present invention includes a group III nitride semiconductor and a group IV nitride formed on the group III nitride semiconductor, where an interface between the group III nitride semiconductor and the group IV nitride has a regular atomic arrangement. Moreover, an arrangement of nitrogen atoms of the group IV nitride in the interface and an arrangement of group III atoms of the group III nitride semiconductor in the interface may be substantially identical.
    Type: Grant
    Filed: April 23, 2007
    Date of Patent: March 29, 2011
    Assignee: Panasonic Corporation
    Inventors: Toshiyuki Takizawa, Tetsuzo Ueda
  • Publication number: 20110058586
    Abstract: A projection/recess structure is formed on a base substrate, and a layered structure of a nitride semiconductor laser is formed on the projection/recess structure. InGaN used for an active layer has an In intake efficiency and a growth rate that greatly vary with the plane direction. By use of this characteristic, an active layer structure low in In content and small in well layer thickness can be formed at a light-outgoing end facet by one-time crystal growth, and thus the transition wavelength of the active layer near the light-outgoing end facet can be shortened. As a result, since optical damage due to light absorption at the light-outgoing end facet can be greatly reduced, a nitride semiconductor laser capable of performing high light-output operation can be implemented.
    Type: Application
    Filed: January 21, 2009
    Publication date: March 10, 2011
    Inventors: Toshiyuki Takizawa, Tetsuzo Ueda
  • Publication number: 20110037101
    Abstract: A semiconductor device includes an undoped GaN layer (13), an undoped AlGaN layer (14), and a p-type GaN layer (15). In the p-type GaN layer (15), highly resistive regions (15a) are selectively formed. Resistance of the highly resistive regions (15a) can be increased by introducing a transition metal, for example, titanium.
    Type: Application
    Filed: March 27, 2009
    Publication date: February 17, 2011
    Inventors: Kazushi Nakazawa, Toshiyuki Takizawa, Tetsuzo Ueda, Daisuke Ueda
  • Publication number: 20110012169
    Abstract: A nitride semiconductor light-emitting device includes a substrate (101) made of silicon, a mask film (102) made of silicon oxide, formed on a principal surface of the substrate (101), and having at least one opening (102a), a seed layer (104) made of GaN selectively formed on the substrate (101) in the opening (102a), an LEG layer (105) formed on a side surface of the seed layer (104), and an n-type GaN layer (106), an active layer (107), and a p-type GaN layer (108) which are formed on the LEG layer (105). The LEG layer (105) is formed by crystal growth using an organic nitrogen material as a nitrogen source.
    Type: Application
    Filed: February 2, 2009
    Publication date: January 20, 2011
    Inventors: Toshiyuki Takizawa, Tetsuzo Ueda, Manabu Usuda
  • Patent number: 7842532
    Abstract: A nitride semiconductor device includes: a substrate having a principal surface; a first nitride semiconductor layer formed on the principal surface of the substrate and includes one or more convex portions whose side surfaces are vertical to the principal surface; and a second nitride semiconductor layer selectively grown on the side surfaces of the one or more convex portions of the first nitride semiconductor layer.
    Type: Grant
    Filed: October 29, 2009
    Date of Patent: November 30, 2010
    Assignee: Panasonic Corporation
    Inventors: Toshiyuki Takizawa, Jun Shimizu, Tetsuzo Ueda
  • Patent number: 7795630
    Abstract: A semiconductor device, which includes an active layer made of a first semiconductor layer formed on a substrate, is designed so that a first oxidized area made of an oxide layer is formed on the active layer. The first oxidized area further aids in reducing a reactive current so that it becomes possible to achieve a semiconductor device having superior device characteristics.
    Type: Grant
    Filed: August 6, 2004
    Date of Patent: September 14, 2010
    Assignee: Panasonic Corporation
    Inventors: Hisashi Nakayama, Tetsuzo Ueda, Masaaki Yuri, Toshiyuki Takizawa
  • Patent number: 7786550
    Abstract: A p-type semiconductor includes a host material that is a semiconductor, an acceptor element and a localized band formation element. The acceptor element is doped to the host material and has fewer valence electrons than valance electrons of at least one of the elements which compose the host material. The localized band formation element is doped to the host material, is isovalent with at least one of the elements which compose the host material, has smaller electronegativity than the electronegativity of the element(s), and forms the localized band which activates holes of an acceptor level.
    Type: Grant
    Filed: March 3, 2004
    Date of Patent: August 31, 2010
    Assignee: Panasonic Corporation
    Inventor: Toshiyuki Takizawa
  • Publication number: 20100178756
    Abstract: A nitride semiconductor device includes: a substrate having a principal surface; a first nitride semiconductor layer formed on the principal surface of the substrate and includes one or more convex portions whose side surfaces are vertical to the principal surface; and a second nitride semiconductor layer selectively grown on the side surfaces of the one or more convex portions of the first nitride semiconductor layer.
    Type: Application
    Filed: October 29, 2009
    Publication date: July 15, 2010
    Applicant: PANASONIC CORPORATION
    Inventors: Toshiyuki TAKIZAWA, Jun Shimizu, Tetsuzo Ueda