Patents by Inventor Naho Itagaki

Naho Itagaki 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: 20150303334
    Abstract: Provided at low cost is a multi-quantum well solar cell such that recombination of carriers generated by light absorption is suppressed and a high photoelectric conversion efficiency is achieved. This multi-quantum well solar cell comprises a substrate, a p-type semiconductor layer, a barrier layer, a well layer, an n-type semiconductor layer, and electrodes, and is characterized in that the barrier layer and the well layer comprise crystals having a wurtzite crystal structure, the well layer is composed of a metal-oxynitride that comprises Zn and at least one element selected from a group consisting of In, Ga, and Al, and a piezoelectric electric field is generated in the well layer. This allows for the provision of a multi-quantum well solar cell such that recombination of carriers generated by light absorption is suppressed and a high photoelectric conversion efficiency is achieved.
    Type: Application
    Filed: March 5, 2013
    Publication date: October 22, 2015
    Applicant: JAPAN SCIENCE AND TECHNOLOGY AGENCY
    Inventors: Naho ITAGAKI, Masaharu SHIRATANI, Giichiro UCHIDA
  • Patent number: 8742412
    Abstract: A thin film transistor includes a gate electrode, a gate insulation layer, a channel layer, a source electrode, and a drain electrode formed on a substrate, in which: the channel layer contains indium, germanium, and oxygen; and the channel layer has a compositional ratio expressed by In/(In+Ge) of 0.5 or more and 0.97 or less.
    Type: Grant
    Filed: January 30, 2009
    Date of Patent: June 3, 2014
    Assignee: Canon Kabushiki Kaisha
    Inventors: Amita Goyal, Naho Itagaki, Tatsuya Iwasaki
  • Patent number: 8679650
    Abstract: A laminated structure comprises a first layer comprising a crystal with six-fold symmetry, and a second layer comprising a metal oxynitride crystal formed on the first layer The second layer comprises at least one element selected from the group consisting of In, Ga, Si, Ge and Al, N, O and Zn, as main elements, and has in-plane orientation.
    Type: Grant
    Filed: October 1, 2009
    Date of Patent: March 25, 2014
    Assignee: Canon Kabushiki Kaisha
    Inventors: Naho Itagaki, Tatsuya Iwasaki, Katsuyuki Hoshino
  • Publication number: 20140070211
    Abstract: Disclosed herein is a field-effect transistor comprising a channel comprised of an oxide semiconductor material including In and Zn. The atomic compositional ratio expressed by In/(In+Zn) is not less than 35 atomic % and not more than 55 atomic %. Ga is not included in the oxide semiconductor material or the atomic compositional ratio expressed by Ga/(In+Zn+Ga) is set to be 30 atomic % or lower when Ga is included therein. The transistor has improved S-value and field-effect mobility.
    Type: Application
    Filed: November 14, 2013
    Publication date: March 13, 2014
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Tatsuya Iwasaki, Toru Den, Naho Itagaki
  • Patent number: 8415198
    Abstract: A production method of a thin film transistor including an active layer including an amorphous oxide semiconductor film, wherein a step of forming the active layer includes a first step of forming the oxide film in an atmosphere having an introduced oxygen partial pressure of 1×10?3 Pa or less, and a second step of annealing the oxide film in an oxidative atmosphere after the first step.
    Type: Grant
    Filed: July 26, 2007
    Date of Patent: April 9, 2013
    Assignee: Canon Kabushiki Kaisha
    Inventors: Naho Itagaki, Toru Den, Nobuyuki Kaji, Ryo Hayashi, Masafumi Sano
  • Patent number: 8314425
    Abstract: A field-effect transistor includes at least a channel layer, a gate insulating layer, a source electrode, a drain electrode, and a gate electrode, which are formed on a substrate. The channel layer is made of an amorphous oxide material that contains at least In and B, and the amorphous oxide material has an element ratio B/(In+B) of 0.05 or higher and 0.29 or lower.
    Type: Grant
    Filed: January 20, 2009
    Date of Patent: November 20, 2012
    Assignee: Canon Kabushiki Kaisha
    Inventors: Tatsuya Iwasaki, Amita Goyal, Naho Itagaki
  • Patent number: 8274078
    Abstract: Provided is an oxynitride semiconductor comprising a metal oxynitride. The metal oxynitride contains Zn and In and at least one element selected from the group consisting of Ga, Sn, Mg, Si, Ge, Y, Ti, Mo, W, and Al. The metal oxynitride has an atomic composition ratio of N, N/(N+O), of 7 atomic percent or more to 80 atomic percent or less.
    Type: Grant
    Filed: April 23, 2008
    Date of Patent: September 25, 2012
    Assignee: Canon Kabushiki Kaisha
    Inventors: Naho Itagaki, Tatsuya Iwasaki, Masatoshi Watanabe, Toru Den
  • Patent number: 8212248
    Abstract: An amorphous oxide at least includes: at least one element selected from the group consisting of In, Zn, and Sn; and Mo. An atomic composition ratio of Mo to a number of all metallic atoms in the amorphous oxide is 0.1 atom % or higher and 5 atom % or lower.
    Type: Grant
    Filed: December 25, 2008
    Date of Patent: July 3, 2012
    Assignee: Canon Kabushiki Kaisha
    Inventors: Naho Itagaki, Amita Goyal, Tatsuya Iwasaki
  • Patent number: 8188471
    Abstract: A field effect transistor is provided including a gate electrode (for example, 15), a source electrode (13), a drain electrode (14) and a channel layer (11) to control current flowing between the source electrode (13) and the drain electrode (14) by applying a voltage to the gate electrode (15). The channel layer (11) is constituted of an amorphous oxide containing In and Si and having a compositional ratio expressed by Si/(In+Si) of not less than 0.05 and not more than 0.40.
    Type: Grant
    Filed: August 29, 2008
    Date of Patent: May 29, 2012
    Assignee: Canon Kabushiki Kaisha
    Inventors: Tatsuya Iwasaki, Naho Itagaki
  • Patent number: 8188467
    Abstract: In a field effect transistor, a channel layer of the field effect transistor is composed of an amorphous oxide including In, Zn, N and O, an atomic composition ratio of N to N and O (N/(N+O)) in the amorphous oxide is equal to or larger than 0.01 atomic percent and equal to or smaller than 3 atomic percent, and the amorphous oxide does not include Ga, or, in a case where the amorphous oxide includes Ga, the number of Ga atoms contained in the amorphous oxide is smaller than the number of N atoms.
    Type: Grant
    Filed: May 22, 2008
    Date of Patent: May 29, 2012
    Assignee: Canon Kabushiki Kaisha
    Inventors: Naho Itagaki, Tatsuya Iwasaki
  • Patent number: 8164090
    Abstract: A field effect transistor has a gate electrode, gate-insulating layer, a channel and a source and drain electrodes connected electrically to the channel, the channel comprising an oxide semiconductor, the source electrode or the drain electrode comprising an oxynitride.
    Type: Grant
    Filed: October 5, 2009
    Date of Patent: April 24, 2012
    Assignee: Canon Kabushiki Kaisha
    Inventors: Tatsuya Iwasaki, Naho Itagaki
  • Patent number: 8084307
    Abstract: A method for manufacturing a thin film transistor containing an channel layer 11 having indium oxide, including forming an indium oxide film as an channel layer and subjecting the formed indium oxide film to an annealing in an oxidizing atmosphere.
    Type: Grant
    Filed: November 9, 2007
    Date of Patent: December 27, 2011
    Assignee: Canon Kabushiki Kaisha
    Inventors: Naho Itagaki, Tatsuya Iwasaki, Toru Den
  • Publication number: 20110175081
    Abstract: A thin film transistor includes a gate electrode, a gate insulation layer, a channel layer, a source electrode, and a drain electrode formed on a substrate, in which: the channel layer contains indium, germanium, and oxygen; and the channel layer has a compositional ratio expressed by In/(In+Ge) of 0.5 or more and 0.97 or less.
    Type: Application
    Filed: January 30, 2009
    Publication date: July 21, 2011
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Amita Goyal, Naho Itagaki, Tatsuya Iwasaki
  • Publication number: 20100276685
    Abstract: An amorphous oxide at least includes: at least one element selected from the group consisting of In, Zn, and Sn; and Mo. An atomic composition ratio of Mo to a number of all metallic atoms in the amorphous oxide is 0.1 atom % or higher and 5 atom % or lower.
    Type: Application
    Filed: December 25, 2008
    Publication date: November 4, 2010
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Naho Itagaki, Amita Goyal, Tatsuya Iwasaki
  • Publication number: 20100264419
    Abstract: A field-effect transistor includes at least a channel layer, a gate insulating layer, a source electrode, a drain electrode, and a gate electrode, which are formed on a substrate. The channel layer is made of an amorphous oxide material that contains at least In and B, and the amorphous oxide material has an element ratio B/(In+B) of 0.05 or higher and 0.29 or lower.
    Type: Application
    Filed: January 20, 2009
    Publication date: October 21, 2010
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Tatsuya Iwasaki, Amita Goyal, Naho Itagaki
  • Publication number: 20100258794
    Abstract: A field effect transistor is provided including a gate electrode (15), a source electrode (13), a drain electrode (14) and a channel layer (11) to control current flowing between the source electrode (13) and the drain electrode (14) by applying a voltage to the gate electrode (15). The channel layer (11) is constituted of an amorphous oxide containing In and Si and having a compositional ratio expressed by Si/(In+Si) of not less than 0.05 and not more than 0.40.
    Type: Application
    Filed: August 29, 2008
    Publication date: October 14, 2010
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Tatsuya Iwasaki, Naho Itagaki
  • Publication number: 20100224870
    Abstract: A field effect transistor includes at least a channel layer, a gate insulation layer, a source electrode, a drain electrode, and a gate electrode. The channel layer is formed from an amorphous oxide material that contains at least In and Mg, and an element ratio, expressed by Mg/(In+Mg), of the amorphous oxide material is 0.1 or higher and 0.48 or lower.
    Type: Application
    Filed: December 2, 2008
    Publication date: September 9, 2010
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Tatsuya Iwasaki, Naho Itagaki
  • Patent number: 7768031
    Abstract: To provide a DC drive type inorganic light emitting device excellent in luminous efficiency, provided is a light emitting device, including: a substrate; and a first layer and a second layer laminated on the substrate, in which the second layer is formed of a first portion containing Zn and at least one element chosen from S and Se as its constituent elements; and a second portion containing at least one element chosen from Cu and Ag and at least one element chosen from S and Se as its constituent elements; the first layer is made of a light emitting layer formed of at least one element chosen from S and Se and of Zn; and, in the second layer, the second portion has a cross section parallel to the substrate which tapers toward the first layer.
    Type: Grant
    Filed: February 21, 2007
    Date of Patent: August 3, 2010
    Assignee: Canon Kabushiki Kaisha
    Inventors: Naho Itagaki, Tomoyuki Oike, Tatsuya Iwasaki, Toru Den
  • Publication number: 20100148170
    Abstract: A field-effect transistor provided with at least a semiconductor layer and a gate electrode disposed over the above-described semiconductor layer with a gate insulating film therebetween, wherein the above-described semiconductor layer includes a first amorphous oxide semiconductor layer having at least one element selected from the group of Zn and In, and a second amorphous oxide semiconductor layer having at least one element selected from the group of Ge and Si and at least one element selected from the group of Zn and In. The composition of the above-described first amorphous oxide semiconductor layer is different from the composition of the above-described second amorphous oxide semiconductor layer.
    Type: Application
    Filed: December 9, 2009
    Publication date: June 17, 2010
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Miki Ueda, Tatsuya Iwasaki, Naho Itagaki, Amita Goyal
  • Publication number: 20100140611
    Abstract: In a field effect transistor, a channel layer of the field effect transistor is composed of an amorphous oxide including In, Zn, N and O, an atomic composition ratio of N to N and O (N/(N+O)) in the amorphous oxide is equal to or larger than 0.01 atomic percent and equal to or smaller than 3 atomic percent, and the amorphous oxide does not include Ga, or, in a case where the amorphous oxide includes Ga, the number of Ga atoms contained in the amorphous oxide is smaller than the number of N atoms.
    Type: Application
    Filed: May 22, 2008
    Publication date: June 10, 2010
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Naho Itagaki, Tatsuya Iwasaki