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).
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Publication number: 20150303334Abstract: 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: ApplicationFiled: March 5, 2013Publication date: October 22, 2015Applicant: JAPAN SCIENCE AND TECHNOLOGY AGENCYInventors: Naho ITAGAKI, Masaharu SHIRATANI, Giichiro UCHIDA
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Patent number: 8742412Abstract: 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: GrantFiled: January 30, 2009Date of Patent: June 3, 2014Assignee: Canon Kabushiki KaishaInventors: Amita Goyal, Naho Itagaki, Tatsuya Iwasaki
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Patent number: 8679650Abstract: 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: GrantFiled: October 1, 2009Date of Patent: March 25, 2014Assignee: Canon Kabushiki KaishaInventors: Naho Itagaki, Tatsuya Iwasaki, Katsuyuki Hoshino
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Publication number: 20140070211Abstract: 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: ApplicationFiled: November 14, 2013Publication date: March 13, 2014Applicant: CANON KABUSHIKI KAISHAInventors: Tatsuya Iwasaki, Toru Den, Naho Itagaki
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Patent number: 8415198Abstract: 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: GrantFiled: July 26, 2007Date of Patent: April 9, 2013Assignee: Canon Kabushiki KaishaInventors: Naho Itagaki, Toru Den, Nobuyuki Kaji, Ryo Hayashi, Masafumi Sano
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Patent number: 8314425Abstract: 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: GrantFiled: January 20, 2009Date of Patent: November 20, 2012Assignee: Canon Kabushiki KaishaInventors: Tatsuya Iwasaki, Amita Goyal, Naho Itagaki
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Patent number: 8274078Abstract: 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: GrantFiled: April 23, 2008Date of Patent: September 25, 2012Assignee: Canon Kabushiki KaishaInventors: Naho Itagaki, Tatsuya Iwasaki, Masatoshi Watanabe, Toru Den
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Patent number: 8212248Abstract: 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: GrantFiled: December 25, 2008Date of Patent: July 3, 2012Assignee: Canon Kabushiki KaishaInventors: Naho Itagaki, Amita Goyal, Tatsuya Iwasaki
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Patent number: 8188471Abstract: 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: GrantFiled: August 29, 2008Date of Patent: May 29, 2012Assignee: Canon Kabushiki KaishaInventors: Tatsuya Iwasaki, Naho Itagaki
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Patent number: 8188467Abstract: 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: GrantFiled: May 22, 2008Date of Patent: May 29, 2012Assignee: Canon Kabushiki KaishaInventors: Naho Itagaki, Tatsuya Iwasaki
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Patent number: 8164090Abstract: 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: GrantFiled: October 5, 2009Date of Patent: April 24, 2012Assignee: Canon Kabushiki KaishaInventors: Tatsuya Iwasaki, Naho Itagaki
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Patent number: 8084307Abstract: 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: GrantFiled: November 9, 2007Date of Patent: December 27, 2011Assignee: Canon Kabushiki KaishaInventors: Naho Itagaki, Tatsuya Iwasaki, Toru Den
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Publication number: 20110175081Abstract: 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: ApplicationFiled: January 30, 2009Publication date: July 21, 2011Applicant: CANON KABUSHIKI KAISHAInventors: Amita Goyal, Naho Itagaki, Tatsuya Iwasaki
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Publication number: 20100276685Abstract: 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: ApplicationFiled: December 25, 2008Publication date: November 4, 2010Applicant: CANON KABUSHIKI KAISHAInventors: Naho Itagaki, Amita Goyal, Tatsuya Iwasaki
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Publication number: 20100264419Abstract: 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: ApplicationFiled: January 20, 2009Publication date: October 21, 2010Applicant: CANON KABUSHIKI KAISHAInventors: Tatsuya Iwasaki, Amita Goyal, Naho Itagaki
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Publication number: 20100258794Abstract: 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: ApplicationFiled: August 29, 2008Publication date: October 14, 2010Applicant: CANON KABUSHIKI KAISHAInventors: Tatsuya Iwasaki, Naho Itagaki
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Publication number: 20100224870Abstract: 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: ApplicationFiled: December 2, 2008Publication date: September 9, 2010Applicant: CANON KABUSHIKI KAISHAInventors: Tatsuya Iwasaki, Naho Itagaki
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Patent number: 7768031Abstract: 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: GrantFiled: February 21, 2007Date of Patent: August 3, 2010Assignee: Canon Kabushiki KaishaInventors: Naho Itagaki, Tomoyuki Oike, Tatsuya Iwasaki, Toru Den
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Publication number: 20100148170Abstract: 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: ApplicationFiled: December 9, 2009Publication date: June 17, 2010Applicant: CANON KABUSHIKI KAISHAInventors: Miki Ueda, Tatsuya Iwasaki, Naho Itagaki, Amita Goyal
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Publication number: 20100140611Abstract: 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: ApplicationFiled: May 22, 2008Publication date: June 10, 2010Applicant: CANON KABUSHIKI KAISHAInventors: Naho Itagaki, Tatsuya Iwasaki