Patents by Inventor Masashi Oota

Masashi Oota 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: 10522347
    Abstract: A method for manufacturing a sputtering target with which an oxide semiconductor film with a small amount of defects can be formed is provided. Alternatively, an oxide semiconductor film with a small amount of defects is formed. A method for manufacturing a sputtering target is provided, which includes the steps of: forming a polycrystalline In-M-Zn oxide (M represents a metal chosen among aluminum, titanium, gallium, yttrium, zirconium, lanthanum, cesium, neodymium, and hafnium) powder by mixing, sintering, and grinding indium oxide, an oxide of the metal, and zinc oxide; forming a mixture by mixing the polycrystalline In-M-Zn oxide powder and a zinc oxide powder; forming a compact by compacting the mixture; and sintering the compact.
    Type: Grant
    Filed: March 7, 2017
    Date of Patent: December 31, 2019
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Shunpei Yamazaki, Masashi Tsubuku, Masashi Oota, Yoichi Kurosawa, Noritaka Ishihara
  • Publication number: 20190341460
    Abstract: The field-effect mobility and reliability of a transistor including an oxide semiconductor film are improved. A semiconductor layer of a transistor is formed using a composite oxide semiconductor in which a first region and a second region are mixed. The first region includes a plurality of first clusters containing one or more of indium, zinc, and oxygen as a main component. The second region includes a plurality of second clusters containing one or more of indium, an element M (M represents Al, Ga, Y, or Sn), zinc, and oxygen. The first region includes a portion in which the plurality of first clusters are connected to each other. The second region includes a portion in which the plurality of second clusters are connected to each other.
    Type: Application
    Filed: July 15, 2019
    Publication date: November 7, 2019
    Inventors: Shunpei YAMAZAKI, Yasutaka NAKAZAWA, Masashi OOTA
  • Patent number: 10461099
    Abstract: A metal oxide film including a crystal part and having highly stable physical properties is provided. The size of the crystal part is less than or equal to 10 nm, which allows the observation of circumferentially arranged spots in a nanobeam electron diffraction pattern of the cross section of the metal oxide film when the measurement area is greater than or equal to 5 nm? and less than or equal to 10 nm?.
    Type: Grant
    Filed: January 25, 2018
    Date of Patent: October 29, 2019
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Masahiro Takahashi, Takuya Hirohashi, Masashi Tsubuku, Noritaka Ishihara, Masashi Oota
  • Publication number: 20190280779
    Abstract: A signal processing circuit includes: a processor configured to adjust phases of reception samples which is supplied at a supply interval, according to a phase adjustment amount; and a processing circuit including a finite impulse response (FIR) filter with taps and configured to process, by the FIR filter, each of the reception samples and output output symbols at an output interval different from the supply interval, the processor is configured to: derive initial values of tap coefficients for the respective taps; and derive the phase adjustment amount such that a center of centroids of the tap coefficients at respective output time points of the output symbols coincides with a center of a number of taps of the FIR filter, the tap coefficients at respective output time points of the output symbols being set according to a deviation between the supply interval and the output interval and the initial values.
    Type: Application
    Filed: January 24, 2019
    Publication date: September 12, 2019
    Applicant: FUJITSU LIMITED
    Inventors: Yuya IMOTO, KAZUHIKO HATAE, Nobukazu KOIZUMI, Yasuo OHTOMO, Masato OOTA, Masashi Sato, Daisuke SASAKI
  • Patent number: 10388738
    Abstract: The field-effect mobility and reliability of a transistor including an oxide semiconductor film are improved. A semiconductor layer of a transistor is formed using a composite oxide semiconductor in which a first region and a second region are mixed. The first region includes a plurality of first clusters containing one or more of indium, zinc, and oxygen as a main component. The second region includes a plurality of second clusters containing one or more of indium, an element M (M represents Al, Ga, Y, or Sn), zinc, and oxygen. The first region includes a portion in which the plurality of first clusters are connected to each other. The second region includes a portion in which the plurality of second clusters are connected to each other.
    Type: Grant
    Filed: March 27, 2017
    Date of Patent: August 20, 2019
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Shunpei Yamazaki, Yasutaka Nakazawa, Masashi Oota
  • Patent number: 10374030
    Abstract: A highly reliable semiconductor device including an oxide semiconductor is provided. Provided is a semiconductor device including an oxide semiconductor layer, an insulating layer in contact with the oxide semiconductor layer, a gate electrode layer overlapping with the oxide semiconductor layer, and a source electrode layer and a drain electrode layer electrically connected to the oxide semiconductor layer. The oxide semiconductor layer includes a first region having a crystal whose size is less than or equal to 10 nm and a second region which overlaps with the insulating layer with the first region provided therebetween and which includes a crystal part whose c-axis is aligned in a direction parallel to a normal vector of the surface of the oxide semiconductor layer.
    Type: Grant
    Filed: August 25, 2017
    Date of Patent: August 6, 2019
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Shunpei Yamazaki, Masahiro Takahashi, Takuya Hirohashi, Masashi Tsubuku, Masashi Oota
  • Patent number: 10316404
    Abstract: A sputtering target including an oxide with a low impurity concentration is provided. Provided is a method for manufacturing a sputtering target, including a first step of preparing a mixture including indium, zinc, an element M (the element M is aluminum, gallium, yttrium, or tin), and oxygen; a second step of raising a temperature of the mixture from a first temperature to a second temperature in a first atmosphere containing nitrogen at a concentration of higher than or equal to 90 vol % and lower than or equal to 100 vol %; and a third step of lowering the temperature of the mixture from the second temperature to a third temperature in a second atmosphere containing oxygen at a concentration of higher than or equal to 10 vol % and lower than or equal to 100 vol %.
    Type: Grant
    Filed: December 16, 2015
    Date of Patent: June 11, 2019
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Shunpei Yamazaki, Yoshinori Yamada, Masashi Oota
  • Publication number: 20180323220
    Abstract: A metal oxide film including a crystal part and having highly stable physical properties is provided. The size of the crystal part is less than or equal to 10 nm, which allows the observation of circumferentially arranged spots in a nanobeam electron diffraction pattern of the cross section of the metal oxide film when the measurement area is greater than or equal to 5 nm? and less than or equal to 10 nm?.
    Type: Application
    Filed: July 2, 2018
    Publication date: November 8, 2018
    Inventors: Masahiro TAKAHASHI, Takuya HIROHASHI, Masashi TSUBUKU, Noritaka ISHIHARA, Masashi OOTA
  • Patent number: 10084096
    Abstract: After a sputtering gas is supplied to a deposition chamber, plasma including an ion of the sputtering gas is generated in the vicinity of a target. The ion of the sputtering gas is accelerated and collides with the target, so that flat-plate particles and atoms of the target are separated from the target. The flat-plate particles are deposited with a gap therebetween so that the flat plane faces a substrate. The atom and the aggregate of the atoms separated from the target enter the gap between the deposited flat-plate particles and grow in the plane direction of the substrate to fill the gap. A film is formed over the substrate. After the deposition, heat treatment is performed at high temperature in an oxygen atmosphere, which forms an oxide with a few oxygen vacancies and high crystallinity.
    Type: Grant
    Filed: September 7, 2017
    Date of Patent: September 25, 2018
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Shunpei Yamazaki, Haruyuki Baba, Akio Suzuki, Hiromi Sawai, Masahiko Hayakawa, Noritaka Ishihara, Masashi Oota
  • Patent number: 10032928
    Abstract: Favorable electrical characteristics are given to a semiconductor device. Furthermore, a semiconductor device having high reliability is provided. One embodiment of the present invention is an oxide semiconductor film having a plurality of electron diffraction patterns which are observed in such a manner that a surface where the oxide semiconductor film is formed is irradiated with an electron beam having a probe diameter whose half-width is 1 nm. The plurality of electron diffraction patterns include 50 or more electron diffraction patterns which are observed in different areas, the sum of the percentage of first electron diffraction patterns and the percentage of second electron diffraction patterns accounts for 100%, the first electron diffraction patterns account for 90% or more, the first electron diffraction pattern includes observed points which indicates that a c-axis is oriented in a direction substantially perpendicular to the surface where the oxide semiconductor film is formed.
    Type: Grant
    Filed: January 27, 2017
    Date of Patent: July 24, 2018
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Akihisa Shimomura, Yasumasa Yamane, Yuhei Sato, Takahisa Ishiyama, Kenichi Okazaki, Chiho Kawanabe, Masashi Oota, Noritaka Ishihara
  • Patent number: 10026847
    Abstract: In a semiconductor element including an oxide semiconductor film as an active layer, stable electrical characteristics are achieved. A semiconductor element includes a base film which is an oxide film at least a surface of which has crystallinity; an oxide semiconductor film having crystallinity over the base film; a gate insulating film over the oxide semiconductor film; a gate electrode overlapping with at least the oxide semiconductor film, over the gate insulating film; and a source electrode and a drain electrode which are electrically connected to the oxide semiconductor film. The base film is a film containing indium and zinc. With the structure, a state of crystals in the oxide semiconductor film reflects that in the base film; thus, the oxide semiconductor film can have crystallinity in a large region in the thickness direction. Accordingly, the electrical characteristics of the semiconductor element including the film can be made stable.
    Type: Grant
    Filed: November 13, 2012
    Date of Patent: July 17, 2018
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Shunpei Yamazaki, Tatsuya Honda, Suzunosuke Hiraishi, Hiroshi Kanemura, Masashi Oota
  • Publication number: 20180151596
    Abstract: A metal oxide film including a crystal part and having highly stable physical properties is provided. The size of the crystal part is less than or equal to 10 nm, which allows the observation of circumferentially arranged spots in a nanobeam electron diffraction pattern of the cross section of the metal oxide film when the measurement area is greater than or equal to 5 nm? and less than or equal to 10 n?.
    Type: Application
    Filed: January 25, 2018
    Publication date: May 31, 2018
    Inventors: Masahiro TAKAHASHI, Takuya HIROHASHI, Masashi TSUBUKU, Noritaka ISHIHARA, Masashi OOTA
  • Patent number: 9911864
    Abstract: Defects in an oxide semiconductor film are reduced in a semiconductor device including the oxide semiconductor film. The electrical characteristics of a semiconductor device including an oxide semiconductor film are improved. The reliability of a semiconductor device including an oxide semiconductor film is improved. A semiconductor device including an oxide semiconductor layer; a metal oxide layer in contact with the oxide semiconductor layer, the metal oxide layer including an In-M oxide (M is Ti, Ga, Y, Zr, La, Ce, Nd, or Hf); and a conductive layer in contact with the metal oxide layer, the conductive layer including copper, aluminum, gold, or silver is provided. In the semiconductor device, y/(x+y) is greater than or equal to 0.75 and less than 1 where the atomic ratio of In to M included in the metal oxide layer is In:M=x:y.
    Type: Grant
    Filed: June 27, 2017
    Date of Patent: March 6, 2018
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Noritaka Ishihara, Masashi Oota, Masashi Tsubuku, Masami Jintyou, Yukinori Shima, Junichi Koezuka, Yasuharu Hosaka, Shunpei Yamazaki
  • Patent number: 9881939
    Abstract: A metal oxide film including a crystal part and having highly stable physical properties is provided. The size of the crystal part is less than or equal to 10 nm, which allows the observation of circumferentially arranged spots in a nanobeam electron diffraction pattern of the cross section of the metal oxide film when the measurement area is greater than or equal to 5 nm? and less than or equal to 10 nm?.
    Type: Grant
    Filed: November 5, 2013
    Date of Patent: January 30, 2018
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Masahiro Takahashi, Takuya Hirohashi, Masashi Tsubuku, Noritaka Ishihara, Masashi Oota
  • Patent number: 9871058
    Abstract: A metal oxide film including a crystal part and having highly stable physical properties is provided. The size of the crystal part is less than or equal to 10 nm, which allows the observation of circumferentially arranged spots in a nanobeam electron diffraction pattern of the cross section of the metal oxide film when the measurement area is greater than or equal to 5 nm? and less than or equal to 10 nm?.
    Type: Grant
    Filed: April 16, 2015
    Date of Patent: January 16, 2018
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Masahiro Takahashi, Takuya Hirohashi, Masashi Tsubuku, Noritaka Ishihara, Masashi Oota
  • Publication number: 20180013005
    Abstract: After a sputtering gas is supplied to a deposition chamber, plasma including an ion of the sputtering gas is generated in the vicinity of a target. The ion of the sputtering gas is accelerated and collides with the target, so that flat-plate particles and atoms of the target are separated from the target. The flat-plate particles are deposited with a gap therebetween so that the flat plane faces a substrate. The atom and the aggregate of the atoms separated from the target enter the gap between the deposited flat-plate particles and grow in the plane direction of the substrate to fill the gap. A film is formed over the substrate. After the deposition, heat treatment is performed at high temperature in an oxygen atmosphere, which forms an oxide with a few oxygen vacancies and high crystallinity.
    Type: Application
    Filed: September 7, 2017
    Publication date: January 11, 2018
    Inventors: Shunpei YAMAZAKI, Haruyuki BABA, Akio SUZUKI, Hiromi SAWAI, Masahiko HAYAKAWA, Noritaka ISHIHARA, Masashi OOTA
  • Publication number: 20170373135
    Abstract: A highly reliable semiconductor device including, an oxide semiconductor is provided. Provided is a semiconductor device including an oxide semiconductor layer, an insulating layer in contact with the oxide semiconductor layer, a gate electrode layer overlapping with the oxide semiconductor layer, and a source electrode layer and a drain electrode layer electrically connected to the oxide semiconductor layer. The oxide semiconductor layer includes a first region having a crystal whose size is less than or equal to 10 nm and a second region which overlaps with the insulating layer with the first region provided therebetween and which includes a crystal part whose c-axis is aligned in a direction parallel to a normal vector of the surface of the oxide semiconductor layer.
    Type: Application
    Filed: August 25, 2017
    Publication date: December 28, 2017
    Inventors: Shunpei YAMAZAKI, Masahiro TAKAHASHI, Takuya HIROHASHI, Masashi TSUBUKU, Masashi OOTA
  • Publication number: 20170350002
    Abstract: A sputtering target including an oxide with a low impurity concentration is provided. Provided is a method for manufacturing a sputtering target, including a first step of preparing a mixture including indium, zinc, an element M (the element M is aluminum, gallium, yttrium, or tin), and oxygen; a second step of raising a temperature of the mixture from a first temperature to a second temperature in a first atmosphere containing nitrogen at a concentration of higher than or equal to 90 vol % and lower than or equal to 100 vol %; and a third step of lowering the temperature of the mixture from the second temperature to a third temperature in a second atmosphere containing oxygen at a concentration of higher than or equal to 10 vol % and lower than or equal to 100 vol %.
    Type: Application
    Filed: December 16, 2015
    Publication date: December 7, 2017
    Inventors: Shunpei Yamazaki, Yoshinori Yamada, Masashi Oota
  • Patent number: 9831274
    Abstract: A metal oxide film including a crystal part and having highly stable physical properties is provided. The size of the crystal part is less than or equal to 10 nm, which allows the observation of circumferentially arranged spots in a nanobeam electron diffraction pattern of the cross section of the metal oxide film when the measurement area is greater than or equal to 5 nm? and less than or equal to 10 nm?.
    Type: Grant
    Filed: June 9, 2015
    Date of Patent: November 28, 2017
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Masahiro Takahashi, Takuya Hirohashi, Masashi Tsubuku, Noritaka Ishihara, Masashi Oota
  • Patent number: 9831353
    Abstract: The semiconductor device includes a first insulator over a substrate, a first oxide semiconductor over the first insulator, a second oxide semiconductor over the first oxide semiconductor, a first conductor and a second conductor in contact with the second oxide semiconductor, a third oxide semiconductor on the second oxide semiconductor and the first and second conductors, a second insulator over the third oxide semiconductor, and a third conductor over the second insulator. At least one of the first oxide semiconductor, the second oxide semiconductor, and the third oxide semiconductor has a crystallinity peak that corresponds to a (hkl) plane (h=0, k=0, l is a natural number) observed by X-ray diffraction using a Cu K-alpha radiation as a radiation source. The peak appears at a diffraction angle 2 theta greater than or equal to 31.3 degrees and less than 33.5 degrees.
    Type: Grant
    Filed: December 18, 2015
    Date of Patent: November 28, 2017
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Takuya Kawata, Masashi Oota, Yusuke Nonaka, Shunpei Yamazaki