Patents by Inventor Tsukasa Nakai

Tsukasa Nakai 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).

  • Patent number: 8431920
    Abstract: According to one embodiment, an information recording and reproducing device includes a recording layer which includes a typical element and a transition element, and stores a state of a first electric resistivity and a state of a second electric resistivity different from the first electric resistivity by a movement of the typical element, and an electrode layer which is disposed at one end of the recording layer to apply a voltage or a current to the recording layer. The recording layer includes a first region which is in contact with the electrode layer and the electrode layer includes a second region which is in contact with the recording layer. The first and second regions are opposite to each other. And the first and second regions include the typical element, and a concentration of the typical element in the second region is higher than that in the first region.
    Type: Grant
    Filed: September 17, 2010
    Date of Patent: April 30, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Chikayoshi Kamata, Takayuki Tsukamoto, Takeshi Yamaguchi, Tsukasa Nakai, Takahiro Hirai, Shinya Aoki, Kohichi Kubo
  • Patent number: 8416606
    Abstract: According to one embodiment, an information recording and reproducing device includes a recording layer and a driving unit. The recording layer includes a first layer containing a first compound. The first compound includes a first positive ion element. The first positive ion element is made of a transition metal element and serves as a first positive ion. The second positive ion element serves as a second positive ion. The driving unit is configured to generate a phase change in the recording layer and to record information by at least one of application of a voltage and application of a current to the recording layer. The coordination number of the first positive ion element at a position of a second coordination of the second positive ion element is 80% or more and less than 100% of the coordination number when the first compound is assumed to be a perfect crystal.
    Type: Grant
    Filed: March 4, 2011
    Date of Patent: April 9, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Takayuki Tsukamoto, Tsukasa Nakai, Chikayoshi Kamata, Mariko Hayashi, Fumihiko Aiga, Takeshi Yamaguchi
  • Patent number: 8395138
    Abstract: A nonvolatile semiconductor memory using carbon related films as variable resistance films includes bottom electrodes formed above a substrate, buffer layers formed on the bottom electrodes and each formed of a film containing nitrogen and containing carbon as a main component, variable resistance films formed on the buffer layers and each formed of a film containing carbon as a main component and the electrical resistivity thereof being changed according to application of voltage or supply of current, and top electrodes formed on the variable resistance films.
    Type: Grant
    Filed: August 21, 2009
    Date of Patent: March 12, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kazuhiko Yamamoto, Kazuyuki Yahiro, Tsukasa Nakai
  • Patent number: 8378331
    Abstract: This nonvolatile semiconductor memory device comprises a memory cell array including memory cells arranged therein. Each of the memory cells is located at respective intersections between first wirings and second wirings and includes a variable resistance element. The variable resistance element comprises a thin film including carbon (C). The thin film includes a side surface along a direction of a current flowing in the memory cell. The side surface includes carbon nitride (CNx).
    Type: Grant
    Filed: February 17, 2010
    Date of Patent: February 19, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yasuhiro Satoh, Tsukasa Nakai, Kazuhiko Yamamoto, Motoya Kishida, Hiroyuki Fukumizu, Yasuhiro Nojiri
  • Patent number: 8339834
    Abstract: According to one embodiment, a non-volatile semiconductor memory device includes: a first line; a second line intersecting with the first line; and a memory cell arranged at a position where the second line intersects with the first line, wherein, the memory cell includes: a variable resistance element; and a negative resistance element connected in series to the variable resistance element.
    Type: Grant
    Filed: September 15, 2010
    Date of Patent: December 25, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tsukasa Nakai, Yasuhiro Nojiri, Shuichi Kuboi, Motoya Kishida, Akiko Nomachi, Masanobu Baba, Hiroyuki Fukumizu
  • Patent number: 8334525
    Abstract: According to one embodiment, a variable resistance layer includes a mixture of a first compound and a second compound. The first compound includes carbon (C) as well as at least one element selected from a group of elements G1. The group of elements G1 consists of hydrogen (H), boron (B), nitrogen (N), silicon (Si), and titanium (Ti). The second compound includes at least one compound selected from a group of compounds G2. The group of compounds G2 consists of silicon oxide (SiO2), silicon oxynitride (SiON), silicon nitride (Si3N4), carbon nitride (C3N4), boron nitride (BN), aluminum nitride (AlN), aluminum oxide (Al2O3), and silicon carbide (SiC). Concentration of the first compound in the variable resistance layer is not less than 30 volume percent, and not more than 70 volume percent.
    Type: Grant
    Filed: June 29, 2010
    Date of Patent: December 18, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tsukasa Nakai, Hiroyuki Fukumizu, Yasuhiro Nojiri, Motoya Kishida, Kazuyuki Yahiro, Yasuhiro Satoh
  • Patent number: 8305797
    Abstract: According to one embodiment, an information recording/reproducing device includes a recording layer and a driver section. The recording layer has a first layer including a first compound. The first compound includes a mixed crystal of a first oxide containing a first metallic element and a second oxide. The second oxide has a crystal structure being same as the first oxide and contains a second metallic element different from the first metallic element. The driver section is configured to produce state change in the recording layer to record information by at least one of application of voltage to the recording layer and passage of current to the recording layer. Composition ratio of an element having a smaller ionic radius of the first and second metallic elements is not less than percolation threshold of a lattice formed of ions of the first and second metallic elements based on the crystal structure.
    Type: Grant
    Filed: March 9, 2011
    Date of Patent: November 6, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Shinya Aoki, Kohichi Kubo, Takayuki Tsukamoto, Takahiro Hirai, Chikayoshi Kamata, Tsukasa Nakai
  • Publication number: 20120273743
    Abstract: A nonvolatile semiconductor memory device includes: a first interconnect; a second interconnect at a position opposing the first interconnect; and a variable resistance layer between the first interconnect and the second interconnect, the variable resistance layer being capable of reversibly changing between a first state and a second state by a voltage applied via the first interconnect and the second interconnect or a current supplied via the first interconnect and the second interconnect, the first state having a first resistivity, the second state having a second resistivity higher than the first resistivity. Wherein the variable resistance layer has a compound of carbon and silicon as a main component and including hydrogen.
    Type: Application
    Filed: November 29, 2010
    Publication date: November 1, 2012
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Shuichi Kuboi, Masayuki Takata, Tsukasa Nakai, Hiroyuki Fukumizu, Yasuhiro Nojiri, Kenichi Ootsuka
  • Patent number: 8269205
    Abstract: According to one embodiment, an information recording and reproducing device includes a first layer, a second layer and a recording layer. The recording layer is provided between the first layer and the second layer and being capable of reversibly changing between a first state having a first resistance and a second state having a second resistance higher than the first resistance. The recording layer includes a first compound layer and a second compound layer. The first compound layer contains a first compound. The first compound includes a first cation element and a second cation element of a type different from the first cation element. The second compound layer contains a second compound. The second compound includes a transition element having a d-orbital partially filled with electron, and the second compound includes a void site capable of storing at least one of the first cation element and the second cation element.
    Type: Grant
    Filed: September 20, 2010
    Date of Patent: September 18, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kohichi Kubo, Chikayoshi Kamata, Takayuki Tsukamoto, Shinya Aoki, Takahiro Hirai, Tsukasa Nakai, Toshiro Hiraoka
  • Patent number: 8264866
    Abstract: According to one embodiment, a nonvolatile memory device includes a memory cell. The memory cell is connected to a first interconnection and a second interconnection and includes a plurality of layers. The plurality of layers includes a memory layer and a carbon nanotube-containing layer which is in contact with the memory layer and contains a plurality of carbon nanotubes.
    Type: Grant
    Filed: September 14, 2010
    Date of Patent: September 11, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroyuki Fukumizu, Yasuhiro Nojiri, Tsukasa Nakai
  • Patent number: 8232042
    Abstract: According to one embodiment, a storage medium comprises a transparent resin substrate on which a groove is formed, a recording layer formed on the groove on the transparent resin substrate, the recording layer using an organic dye material and recording information with a light beam of 620 nm or less in wavelength, a reflection layer formed on the recording layer, and a prevention layer formed between the recording layer and the reflection layer, the prevention layer preventing degradation of characteristics of the reflection layer.
    Type: Grant
    Filed: March 30, 2006
    Date of Patent: July 31, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tsukasa Nakai, Seiji Morita, Koji Takazawa, Yasuaki Ootera, Naoki Morishita, Kazuyo Umezawa, Hideo Ando
  • Patent number: 8207518
    Abstract: According to one embodiment, an information recording and reproducing device includes a first layer, a second layer and a recording layer. The recording layer is provided between the first layer and the second layer and being capable of reversibly changing between a first state having a first resistance and a second state having a second resistance higher than the first resistance by a current supplied via the first layer and the second layer. The recording layer includes a first compound layer and an insulating layer. The first compound layer contains a first compound. The first compound includes a first cation element and a second cation element of a type different from the first cation element. The insulating layer contains a third compound, and the third compound includes an element selected from group 1 to 4 elements and group 12 to 17 elements in the periodic table.
    Type: Grant
    Filed: September 20, 2010
    Date of Patent: June 26, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kohichi Kubo, Chikayoshi Kamata, Takayuki Tsukamoto, Shinya Aoki, Takahiro Hirai, Tsukasa Nakai, Toshiro Hiraoka
  • Publication number: 20120061732
    Abstract: According to one embodiment, an information recording/reproducing device including a semiconductor substrate, a first interconnect layer on the semiconductor substrate, a first memory cell array layer on the first interconnect layer, and a second interconnect layer on the first memory cell array layer. The first memory cell array layer comprises an insulating layer having an alignment mark, and a stacked layer structure on the insulating layer and including a storage layer and an electrode layer. All of the layers in the stacked layer structure comprises a material with a permeability of visible light of 1% or more.
    Type: Application
    Filed: September 9, 2011
    Publication date: March 15, 2012
    Inventors: Takahiro HIRAI, Tsukasa NAKAI, Kohichi KUBO, Chikayoshi KAMATA, Takayuki TSUKAMOTO, Shinya AOKI
  • Patent number: 8089796
    Abstract: According to one embodiment, an information recording and reproducing device includes a first layer, a second layer and a recording layer. The recording layer is provided between the first and second layers and is capable of reversibly transitioning between a first state and a second state with a resistance higher than in the first state. One of the first and second layers includes a resistivity distribution layer perpendicular to a stacking direction of the first and second layers, and the recording layer. The resistivity distribution layer includes a low and a high resistivity portion. Resistivity of the high resistivity portion is higher than resistivity of the low resistivity portion. The low resistivity portion contains a transition element identical to a transition element contained in the high resistivity portion.
    Type: Grant
    Filed: September 20, 2010
    Date of Patent: January 3, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Takayuki Tsukamoto, Takeshi Yamaguchi, Chikayoshi Kamata, Tsukasa Nakai, Takahiro Hirai, Shinya Aoki, Kohichi Kubo
  • Publication number: 20110303888
    Abstract: According to one embodiment, a nonvolatile memory device includes a memory cell connected to a first interconnect and a second interconnect. The memory cell includes a plurality of layers. The plurality of layers includes a carbon-containing memory layer sandwiched between a first electrode film and a second electrode film and a carbon-containing barrier layer provided at least one of between the first electrode film and the memory layer and between the second electrode film and the memory layer. The barrier layer has lower electrical resistivity than the memory layer.
    Type: Application
    Filed: March 10, 2011
    Publication date: December 15, 2011
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Hiroyuki FUKUMIZU, Yasuhiro Nojiri, Tsukasa Nakai, Kazuhiko Yamamoto
  • Publication number: 20110216576
    Abstract: According to one embodiment, an information recording/reproducing device includes a recording layer and a driver section. The recording layer has a first layer including a first compound. The first compound includes a mixed crystal of a first oxide containing a first metallic element and a second oxide. The second oxide has a crystal structure being same as the first oxide and contains a second metallic element different from the first metallic element. The driver section is configured to produce state change in the recording layer to record information by at least one of application of voltage to the recording layer and passage of current to the recording layer. Composition ratio of an element having a smaller ionic radius of the first and second metallic elements is not less than percolation threshold of a lattice formed of ions of the first and second metallic elements based on the crystal structure.
    Type: Application
    Filed: March 9, 2011
    Publication date: September 8, 2011
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Shinya Aoki, Kohichi Kubo, Takayuki Tsukamoto, Takahiro Hirai, Chikayoshi Kamata, Tsukasa Nakai
  • Publication number: 20110216582
    Abstract: According to one embodiment, an information recording and reproducing device includes a recording layer and a driving unit. The recording layer includes a first layer containing a first compound. The first compound includes a first positive ion element. The first positive ion element is made of a transition metal element and serves as a first positive ion. The second positive ion element serves as a second positive ion. The driving unit is configured to generate a phase change in the recording layer and to record information by at least one of application of a voltage and application of a current to the recording layer. The coordination number of the first positive ion element at a position of a second coordination of the second positive ion element is 80% or more and less than 100% of the coordination number when the first compound is assumed to be a perfect crystal.
    Type: Application
    Filed: March 4, 2011
    Publication date: September 8, 2011
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Takayuki Tsukamoto, Tsukasa Nakai, Chikayoshi Kamata, Mariko Hayashi, Fumihiko Aiga, Takeshi Yamaguchi
  • Publication number: 20110205781
    Abstract: According to one embodiment, a non-volatile semiconductor memory device includes: a first line; a second line intersecting with the first line; and a memory cell arranged at a position where the second line intersects with the first line, wherein, the memory cell includes: a variable resistance element; and a negative resistance element connected in series to the variable resistance element.
    Type: Application
    Filed: September 15, 2010
    Publication date: August 25, 2011
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Tsukasa Nakai, Yasuhiro Nojiri, Shuichi Kuboi, Motoya Kishida, Akiko Nomachi, Masanobu Baba, Hiroyuki Fukumizu
  • Publication number: 20110069525
    Abstract: According to one embodiment, a nonvolatile memory device includes a memory cell. The memory cell is connected to a first interconnection and a second interconnection and includes a plurality of layers. The plurality of layers includes a memory layer and a carbon nanotube-containing layer which is in contact with the memory layer and contains a plurality of carbon nanotubes.
    Type: Application
    Filed: September 14, 2010
    Publication date: March 24, 2011
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Hiroyuki FUKUMIZU, Yasuhiro Nojiri, Tsukasa Nakai
  • Publication number: 20110068319
    Abstract: According to one embodiment, an information recording and reproducing device includes a stacked body. The stacked body includes a first layer, a second layer and a recording layer provided between the first layer and the second layer. The recording layer includes a phase-change material and a crystal nucleus. The phase-change material is capable of reversely changing between a crystal state and an amorphous state by a current supplied via the first layer and the second layer. The crystal nucleus is provided in contact with the phase-change material and includes a crystal nucleus material having a crystal structure identical to a crystal structure of the crystal state of the phase-change material, and a crystal nucleus coating provided on a surface of the crystal nucleus material and having a composition different from a composition of the crystal nucleus material.
    Type: Application
    Filed: September 20, 2010
    Publication date: March 24, 2011
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Takayuki TSUKAMOTO, Tsukasa NAKAI, Akira KIKITSU, Takeshi YAMAGUCHI, Sumio ASHIDA