Patents by Inventor Mitsuru Takenaka

Mitsuru Takenaka 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: 20230368854
    Abstract: A photonic spin register includes: a shift register unit including a magnetic material layer having a shape extending in one direction; and a write unit configured to write spin information into a magnetic domain in the magnetic material layer by transferring information included in an optical signal that is a pulse amplitude-modulated and serial input signal, to a spin state of the magnetic domain in the magnetic material layer by means of a photocurrent corresponding to the optical signal or by irradiation with the optical signal. When a shift current flows through the shift register unit in the one direction, a domain wall is configured to move in the magnetic material layer, thereby allowing the spin information to move and be buffered in the magnetic material layer.
    Type: Application
    Filed: July 19, 2023
    Publication date: November 16, 2023
    Applicant: The University of Tokyo
    Inventors: Satoru Nakatsuji, Junji Yumoto, Ryo Shimano, Masamitsu Hayashi, Mitsuru Takenaka, Yusuke Horinouchi
  • Patent number: 11227953
    Abstract: A tunneling field effect transistor according to an embodiment of the present invention includes: a first semiconductor layer having a first conductive type; a second semiconductor layer having a second conductive type and realizing a heterojunction with respect to the first semiconductor layer in a first region; a gate insulating layer over the second semiconductor layer in the first region; a gate electrode layer over the gate insulating layer; a first electrode layer electrically connected to the first semiconductor layer; a second electrode layer electrically connected to the second semiconductor layer; and a first insulating layer interposed between the first semiconductor layer and the second semiconductor layer in a second region adjacent to the first region toward the second electrode layer.
    Type: Grant
    Filed: November 28, 2018
    Date of Patent: January 18, 2022
    Assignee: JAPAN SCIENCE AND TECHNOLOGY AGENCY
    Inventors: Kimihiko Kato, Shinichi Takagi, Mitsuru Takenaka, Hitoshi Tabata, Hiroaki Matsui
  • Patent number: 11054675
    Abstract: Provided is an optical modulator which is small in optical loss, is small in a size, and is low in required voltage and is operable to perform high-speed operation. The optical phase modulator 100 comprises a rib-type waveguide structure 110 including: a PN junction 106 which is formed of Si and is formed in a lateral direction on a substrate; and an Si1-xGex layer 108 which is constituted of at least one layer and is doped with an impurity to a p-type and is superposed on the PN junction 106 so as to be electrically connected to the PN junction 106. The rib-type waveguide structure 110 has a substantially uniform structure along a light propagation direction, and in a direction parallel with the substrate and perpendicular to the light propagation direction, a position of a junction interface 106a of the PN junction 106 is offset from a center of the Si1-xGex layer 108.
    Type: Grant
    Filed: August 24, 2018
    Date of Patent: July 6, 2021
    Assignees: PHOTONICS ELECTRONICS TECHNOLOGY RESEARCH ASSOCIATION, THE UNIVERSITY OF TOKYO
    Inventors: Junichi Fujikata, Shigeki Takahashi, Mitsuru Takenaka
  • Patent number: 10983411
    Abstract: A MOS optical modulator having high modulation efficiency and a method of manufacturing the same are provided. A MOS optical modulator includes: a p-type Si layer constituting an optical waveguide; a gate insulating film provided on the optical waveguide; a gate layer provided on the gate insulating film and formed of an n-type group III-V semiconductor; a first contact portion connected to the gate layer; and a second contact portion connected to the Si layer.
    Type: Grant
    Filed: August 17, 2017
    Date of Patent: April 20, 2021
    Assignee: THE UNIVERSITY OF TOKYO
    Inventors: Mitsuru Takenaka, Jae-Hoon Han, Shinichi Takagi
  • Publication number: 20210005758
    Abstract: A tunneling field effect transistor according to an embodiment of the present invention includes: a first semiconductor layer having a first conductive type; a second semiconductor layer having a second conductive type and realizing a heterojunction with respect to the first semiconductor layer in a first region; a gate insulating layer over the second semiconductor layer in the first region; a gate electrode layer over the gate insulating layer; a first electrode layer electrically connected to the first semiconductor layer; a second electrode layer electrically connected to the second semiconductor layer; and a first insulating layer interposed between the first semiconductor layer and the second semiconductor layer in a second region adjacent to the first region toward the second electrode layer.
    Type: Application
    Filed: November 28, 2018
    Publication date: January 7, 2021
    Inventors: Kimihiko KATO, Shinichi TAKAGI, Mitsuru TAKENAKA, Hitoshi TABATA, Hiroaki MATSUI
  • Publication number: 20200301177
    Abstract: Provided is an optical modulator which is small in optical loss, is small in a size, and is low in required voltage and is operable to perform high-speed operation. The optical phase modulator 100 comprises a rib-type waveguide structure 110 including: a PN junction 106 which is formed of Si and is formed in a lateral direction on a substrate; and an Si1-xGex layer 108 which is constituted of at least one layer and is doped with an impurity to a p-type and is superposed on the PN junction 106 so as to be electrically connected to the PN junction 106. The rib-type waveguide structure 110 has a substantially uniform structure along a light propagation direction, and in a direction parallel with the substrate and perpendicular to the light propagation direction, a position of a junction interface 106a of the PN junction 106 is offset from a center of the Si1-xGex layer 108.
    Type: Application
    Filed: August 24, 2018
    Publication date: September 24, 2020
    Inventors: Junichi Fujikata, Shigeki Takahashi, Mitsuru Takenaka
  • Publication number: 20190285964
    Abstract: A MOS optical modulator having high modulation efficiency and a method of manufacturing the same are provided. A MOS optical modulator includes: a p-type Si layer constituting an optical waveguide; a gate insulating film provided on the optical waveguide; a gate layer provided on the gate insulating film and formed of an n-type group III-V semiconductor; a first contact portion connected to the gate layer; and a second contact portion connected to the Si layer.
    Type: Application
    Filed: August 17, 2017
    Publication date: September 19, 2019
    Inventors: MITSURU TAKENAKA, JAE-HOON HAN, SHINICHI TAKAGI
  • Patent number: 10146070
    Abstract: An optical phase modulator 100 according to an embodiment of this disclosure comprises a rib-type waveguide structure 110 comprising: a PN junction 106 comprising Si and formed in a lateral direction on a substrate; and a Si1-xGex layer 108 that is doped with a p-type impurity and comprises at least one layer laminated on the PN junction 106, so as to be electrically connected to the PN junction 106.
    Type: Grant
    Filed: February 2, 2016
    Date of Patent: December 4, 2018
    Assignee: PHOTONICS ELECTRONICS TECHNOLOGY RESEARCH ASSOCIATION
    Inventors: Junichi Fujikata, Shigeki Takahashi, Mitsuru Takenaka, Younghyun Kim
  • Publication number: 20180024410
    Abstract: An optical phase modulator 100 according to an embodiment of this disclosure comprises a rib-type waveguide structure 110 comprising: a PN junction 106 comprising Si and formed in a lateral direction on a substrate; and a Si1-xGex layer 108 that is doped with a p-type impurity and comprises at least one layer laminated on the PN junction 106, so as to be electrically connected to the PN junction 106.
    Type: Application
    Filed: February 2, 2016
    Publication date: January 25, 2018
    Inventors: Junichi FUJIKATA, Shigeki TAKAHASHI, Mitsuru TAKENAKA, Younghyun KIM
  • Patent number: 9117658
    Abstract: There is provided a fabrication technique of a MOS structure that has a small EOT without increasing the interface trap density. More specifically, provided is a method of producing a semiconductor wafer that includes a semiconductor crystal layer, an interlayer made of an oxide, nitride, or oxynitride of a semiconductor crystal constituting the semiconductor crystal layer, and a first insulating layer made of an oxide and in which the semiconductor crystal layer, the interlayer, and the first insulating layer are arranged in the stated order. The method includes (a) forming the first insulating layer on an original semiconductor crystal layer, and (b) exposing a surface of the first insulating layer with a nitrogen plasma to nitride, oxidize, or oxynitride a part of the original semiconductor crystal layer, thereby forming the interlayer, together with the semiconductor crystal layer that is the rest of the original semiconductor crystal layer.
    Type: Grant
    Filed: August 23, 2013
    Date of Patent: August 25, 2015
    Assignees: SUMITOMO CHEMICAL COMPANY, LIMITED, THE UNIVERSITY OF TOKYO
    Inventors: Mitsuru Takenaka, Shinichi Takagi, Jaehoon Han, Tomoyuki Takada, Takenori Osada, Masahiko Hata
  • Patent number: 9112035
    Abstract: A semiconductor substrate includes a substrate, an insulating layer, and a semiconductor layer. The insulating layer is over and in contact with the substrate. The insulating layer includes at least one of an amorphous metal oxide and an amorphous metal nitride. The semiconductor layer is over and in contact with the insulating layer. The semiconductor layer is formed by crystal growth.
    Type: Grant
    Filed: March 2, 2012
    Date of Patent: August 18, 2015
    Assignees: SUMITOMO CHEMICAL COMPANY, LIMITED, THE UNIVERSITY OF TOKYO, NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND TECHNOLOGY
    Inventors: Hisashi Yamada, Masahiko Hata, Masafumi Yokoyama, Mitsuru Takenaka, Shinichi Takagi, Tetsuji Yasuda, Hideki Takagi, Yuji Urabe
  • Patent number: 8901656
    Abstract: Provided is a semiconductor wafer including a base wafer, a first insulating layer, and a semiconductor layer. Here, the base wafer, the first insulating layer and the semiconductor layer are arranged in an order of the base wafer, the first insulating layer and the semiconductor layer, the first insulating layer is made of an amorphous metal oxide or an amorphous metal nitride, the semiconductor layer includes a first crystal layer and a second crystal layer, the first crystal layer and the second crystal layer are arranged in an order of the first crystal layer and the second crystal layer in such a manner that the first crystal layer is positioned closer to the base wafer, and the electron affinity Ea1 of the first crystal layer is larger than the electron affinity Ea2 of the second crystal layer.
    Type: Grant
    Filed: August 30, 2013
    Date of Patent: December 2, 2014
    Assignees: Sumitomo Chemical Company, Limited, The University of Tokyo, National Institute of Advanced Industrial Science and Technology
    Inventors: Takeshi Aoki, Hisashi Yamada, Noboru Fukuhara, Masahiko Hata, Masafumi Yokoyama, SangHyeon Kim, Mitsuru Takenaka, Shinichi Takagi, Tetsuji Yasuda
  • Patent number: 8779471
    Abstract: Provided is a field-effect transistor including a gate insulating layer, a first semiconductor crystal layer in contact with the gate insulating layer, and a second semiconductor crystal layer lattice-matching or pseudo lattice-matching the first semiconductor crystal layer. Here, the gate insulating layer, the first semiconductor crystal layer, and the second semiconductor crystal layer are arranged in the order of the gate insulating layer, the first semiconductor crystal layer, and the second semiconductor crystal layer, the first semiconductor crystal layer is made of Inx1Ga1-x1Asy1P1-y1 (0<x1?1, 0?y1?1), the second semiconductor crystal layer is made of Inx2Ga1-x2Asy2P1-y2 (0?x2?1, 0?y2?1, y2?y1), and the electron affinity Ea1 of the first semiconductor crystal layer is lower than the electron affinity Ea2 of the second semiconductor crystal layer.
    Type: Grant
    Filed: March 6, 2012
    Date of Patent: July 15, 2014
    Assignees: Sumitomo Chemical Company, Limited, The University of Tokyo, National Institute of Advanced Industrial Science and Technology
    Inventors: Masahiko Hata, Hisashi Yamada, Noboru Fukuhara, Shinichi Takagi, Mitsuru Takenaka, Masafumi Yokoyama, Tetsuji Yasuda, Yuji Urabe, Noriyuki Miyata, Taro Itatani, Hiroyuki Ishii
  • Publication number: 20140091393
    Abstract: There is provided a semiconductor device including: a first source and a first drain of a first-channel-type MISFET formed on a first semiconductor crystal layer, which are made of a compound having an atom constituting the first semiconductor crystal layer and a nickel atom, a compound having an atom constituting the first semiconductor crystal layer and a cobalt atom, or a compound having an atom constituting the first semiconductor crystal layer, a nickel atom, and a cobalt atom; and a second source and a second drain of a second-channel-type MISFET formed on a second semiconductor crystal layer, which are made of a compound having an atom constituting the second semiconductor crystal layer and a nickel atom, a compound having an atom constituting the second semiconductor crystal layer and a cobalt atom, or a compound having an atom constituting the second semiconductor crystal layer, a nickel atom, and a cobalt atom.
    Type: Application
    Filed: December 6, 2013
    Publication date: April 3, 2014
    Applicants: SUMITOMO CHEMICAL COMPANY, LIMITED, NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND TECHNOLOGY, THE UNIVERSTIY OF TOKYO
    Inventors: Masahiko HATA, Hisashi YAMADA, Masafumi YOKOYAMA, SangHyeon Kim, Mitsuru TAKENAKA, Shinichi TAKAGI, Tetsuji YASUDA
  • Publication number: 20140091398
    Abstract: Provided is a semiconductor device including a first source and a first drain of a P-channel-type MISFET formed on a Ge wafer, which are made of a compound having a Ge atom and a nickel atom, a compound having a Ge atom and a cobalt atom, or a compound having a Ge atom, a nickel atom, and a cobalt atom, and a second source and a second drain of an N-channel-type MISFET formed on the Group III-V compound semiconductor, which are made of a compound having a Group III atom, a Group V atom, and a nickel atom, a compound having a Group III atom, a Group V atom, and a cobalt atom, or a compound having a Group III atom, a Group V atom, a nickel atom, and a cobalt atom.
    Type: Application
    Filed: December 6, 2013
    Publication date: April 3, 2014
    Applicants: SUMITOMO CHEMICAL COMPANY, LIMITED, NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND TECHNOLOGY, THE UNIVERSITY OF TOKYO
    Inventors: Masahiko HATA, Hisashi YAMADA, Masafumi YOKOYAMA, SangHyeon Kim, Rui ZHANG, Mitsuru TAKENAKA, Shinichi TAKAGI, Tetsuji YASUDA
  • Publication number: 20140054726
    Abstract: There is provided a fabrication technique of a MOS structure that has a small EOT without increasing the interface trap density. More specifically, provided is a method of producing a semiconductor wafer that includes a semiconductor crystal layer, an interlayer made of an oxide, nitride, or oxynitride of a semiconductor crystal constituting the semiconductor crystal layer, and a first insulating layer made of an oxide and in which the semiconductor crystal layer, the interlayer, and the first insulating layer are arranged in the stated order. The method includes (a) forming the first insulating layer on an original semiconductor crystal layer, and (b) exposing a surface of the first insulating layer with a nitrogen plasma to nitride, oxidize, or oxynitride a part of the original semiconductor crystal layer, thereby forming the interlayer, together with the semiconductor crystal layer that is the rest of the original semiconductor crystal layer.
    Type: Application
    Filed: August 23, 2013
    Publication date: February 27, 2014
    Applicants: THE UNIVERSITY OF TOKYO, SUMITOMO CHEMICAL COMPANY, LIMITED
    Inventors: Mitsuru TAKENAKA, Shinichi TAKAGI, Jaehoon HAN, Tomoyuki TAKADA, Takenori OSADA, Masahiko HATA
  • Publication number: 20130341721
    Abstract: Provided is a semiconductor wafer including a base wafer, a first insulating layer, and a semiconductor layer. Here, the base wafer, the first insulating layer and the semiconductor layer are arranged in an order of the base wafer, the first insulating layer and the semiconductor layer, the first insulating layer is made of an amorphous metal oxide or an amorphous metal nitride, the semiconductor layer includes a first crystal layer and a second crystal layer, the first crystal layer and the second crystal layer are arranged in an order of the first crystal layer and the second crystal layer in such a manner that the first crystal layer is positioned closer to the base wafer, and the electron affinity Ea1 of the first crystal layer is larger than the electron affinity Ea2 of the second crystal layer.
    Type: Application
    Filed: August 30, 2013
    Publication date: December 26, 2013
    Applicants: SUMITOMO CHEMICAL COMPANY, LIMITED, NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND TECHNOLOGY, THE UNIVERSITY OF TOKYO
    Inventors: Takeshi AOKI, Hisashi YAMADA, Noboru FUKUHARA, Masahiko HATA, Masafumi YOKOYAMA, SangHyeon KIM, Mitsuru TAKENAKA, Shinichi TAKAGI, Tetsuji YASUDA
  • Patent number: 8431459
    Abstract: It is an objective of the present invention to form a favorable interface between an oxide layer and a group 3-5 compound semiconductor using a practical and simple method. Provided is a semiconductor wafer comprising a first semiconductor layer that is a group 3-5 compound not containing arsenic and that lattice matches or pseudo-lattice matches with InP; and a second semiconductor layer that is formed to contact the first semiconductor layer, is a group 3-5 compound semiconductor layer that lattice matches or pseudo-lattice matches with InP, and can be selectively oxidized relative to the first semiconductor layer.
    Type: Grant
    Filed: March 26, 2009
    Date of Patent: April 30, 2013
    Assignee: The University of Tokyo
    Inventors: Mitsuru Takenaka, Shinichi Takagi, Masahiko Hata, Osamu Ichikawa
  • Publication number: 20120228673
    Abstract: Provided is a field-effect transistor including a gate insulating layer, a first semiconductor crystal layer in contact with the gate insulating layer, and a second semiconductor crystal layer lattice-matching or pseudo lattice-matching the first semiconductor crystal layer. Here, the gate insulating layer, the first semiconductor crystal layer, and the second semiconductor crystal layer are arranged in the order of the gate insulating layer, the first semiconductor crystal layer, and the second semiconductor crystal layer, the first semiconductor crystal layer is made of Inx1Ga1-x1Asy1P1-y1 (0<x1?1, 0?y1?1), the second semiconductor crystal layer is made of Inx2Ga1-x2Asy2P1-y2 (0?x2?1, 0?y2?1, y2?y1), and the electron affinity Ea1 of the first semiconductor crystal layer is lower than the electron affinity Ea2 of the second semiconductor crystal layer.
    Type: Application
    Filed: March 6, 2012
    Publication date: September 13, 2012
    Applicants: SUMITOMO CHEMICAL COMPANY, National Institute of Advanced Industrial Science and Technology, The University of Tokyo
    Inventors: Masahiko HATA, Hisashi Yamada, Noboru Fukuhara, Shinichi Takagi, Mitsuru Takenaka, Masafumi Yokoyama, Tetsuji Yasuda, Yuji Urabe, Noriyuki Miyata, Taro Itatani, Hiroyuki Ishii
  • Publication number: 20120205747
    Abstract: A semiconductor substrate includes a substrate, an insulating layer, and a semiconductor layer. The insulating layer is over and in contact with the substrate. The insulating layer includes at least one of an amorphous metal oxide and an amorphous metal nitride. The semiconductor layer is over and in contact with the insulating layer. The semiconductor layer is formed by crystal growth.
    Type: Application
    Filed: March 2, 2012
    Publication date: August 16, 2012
    Applicants: THE UNIVERSITY OF TOKYO, SUMITOMO CHEMICAL CO., LTD.
    Inventors: Hisashi YAMADA, Masahiko HATA, Masafumi YOKOYAMA, Mitsuru TAKENAKA, Shinichi TAKAGI, Tetsuji YASUDA, Hideki TAKAGI, Yuji URABE