Patents Assigned to Dowa Electronics Materials Co., Ltd.
  • Patent number: 11894502
    Abstract: A method of manufacturing a semiconductor optical device of this disclosure includes the steps of forming an etch stop layer on an InP growth substrate, the etch stop layer having a thickness of 100 nm or less; and forming a semiconductor laminate on the etch stop layer by stacking a plurality of InGaAsP-based III-V group compound semiconductor layers containing at least In and P. Further, an intermediate article of a semiconductor optical device of the present disclosure includes an InP growth substrate; an etch stop layer formed on the InP growth substrate, the etch stop layer having a thickness of 100 nm or less; and a semiconductor laminate formed on the etch stop layer, including a plurality of InGaAsP-based III-V group compound semiconductor layers containing at least In and P stacked one another.
    Type: Grant
    Filed: March 27, 2019
    Date of Patent: February 6, 2024
    Assignee: DOWA Electronics Materials Co., Ltd.
    Inventors: Yuta Koshika, Yoshitaka Kadowaki, Tetsuya Ikuta
  • Patent number: 11894171
    Abstract: Provided is an Al-containing hexagonal ferrite magnetic powder which produces an excellent durability-improving effect on a magnetic recording medium, wherein uniform pulverization of the magnetic powder can be easily achieved by dispersion treatment in preparation of a magnetic coating material even in cases where the magnetic powder has a small primary particle size or has a composition which is likely to produce hard secondary particles. The magnetic powder for a magnetic recording medium is an Al-containing hexagonal ferrite magnetic powder having an Al/Fe molar ratio of 0.030 to 0.200, and has a particle size distribution in which the volume ratio of particles having a particle size of 30 ?m or more as measured by a laser diffraction particle size distribution analyzer with a dispersion pressure of 100 kPa is 5.0% or less, and an activation volume Vact of 1800 nm3 or less.
    Type: Grant
    Filed: November 14, 2019
    Date of Patent: February 6, 2024
    Assignees: DOWA ELECTRONICS MATERIALS CO., LTD., FUJIFILM CORPORATION
    Inventors: Hirohisa Omoto, Shuji Kaneda, Satoshi Shiki, Hiroyuki Suzuki, Toshio Tada
  • Patent number: 11888090
    Abstract: Provided is a semiconductor light-emitting element having improved light emission output. The semiconductor light-emitting element includes a light-emitting layer having a layered structure in which a first III-V compound semiconductor layer and a second III-V compound semiconductor layer having different composition ratios are repeatedly stacked. The first and second III-V compound semiconductor layers each contain three or more types of elements that are selected from Al, Ga, and In and from As, Sb, and P. The composition wavelength difference between the composition wavelength of the first III-V compound semiconductor layer and the composition wavelength of the second III-V compound semiconductor layer is 50 nm or less. The ratio of the lattice constant difference between the lattice constant of the first III-V compound semiconductor layer and the lattice constant of the second III-V compound semiconductor layer is not less than 0.05% and not more than 0.60%.
    Type: Grant
    Filed: December 12, 2019
    Date of Patent: January 30, 2024
    Assignee: DOWA Electronics Materials Co., Ltd.
    Inventors: Yuta Koshika, Yoshitaka Kadowaki
  • Publication number: 20240030386
    Abstract: Provided is a semiconductor light-emitting device for which detrimental effects such as discoloration of an electrode or emission failure due to migration are suppressed even when a joint material containing Ag is used, and a method of producing the same. The semiconductor light-emitting device includes a p-type semiconductor layer, a p-type electrode provided on the p-type semiconductor layer, and a pad provided on the p-type electrode. The p-type electrode at least has an ohmic metal layer placed on the p-type semiconductor layer side and a barrier layer that is placed closer to the pad than the ohmic metal layer and includes a TiN layer. In a top view, when a region of the barrier layer that does not overlap an electrical connection region between the pad and the barrier layer is defined as a surface diffusion inhibiting surface, the surface diffusion inhibiting surface is formed in a circular pattern.
    Type: Application
    Filed: May 18, 2021
    Publication date: January 25, 2024
    Applicant: DOWA Electronics Materials Co., Ltd.
    Inventor: Takashi MOMOSE
  • Patent number: 11866346
    Abstract: A composite oxide powder including a composition formula (1), wherein the ratio ?/? of a surface area value ? (m2/g) calculated by a BET one-point method to a surface area value ? (m2/g) calculated from a formula (2) is greater than 1.0 and equal to or less than 1.5 and the surface area value ? is equal to or less than 20 m2/g. ABO3-? (1) (wherein A is one or more types of elements (La, Sr, Sm, Ca and Ba), B is one or more types of elements (Fe, Co, Ni and Mn) and 0??<1); and surface area value ? (m2/g)=specific surface area value ?-surface area value ?(2) (the specific surface area value ? (m2/g) is a value in a total pore size range measured by a mercury intrusion method. The specific surface area value ? (m2/g) is a value in a range of pore sizes that are larger than a 50% cumulative particle size.
    Type: Grant
    Filed: August 7, 2020
    Date of Patent: January 9, 2024
    Assignee: DOWA ELECTRONICS MATERIALS CO., LTD.
    Inventors: Kazumasa Ikari, Shintaro Ogawa, Toshihiko Ueyama
  • Publication number: 20230392291
    Abstract: Provided is a GaAs wafer that can suitably be used to produce LiDAR sensors in particular and a method of producing a GaAs ingot that can be used to obtain such a GaAs wafer. The GaAs wafer has a silicon concentration of 5.0×1017 cm?3 or more and less than 3.5×1018 cm?3, an indium concentration of 3.0×1017 cm?3 or more and less than 3.0×1019 cm?3, and a boron concentration of 1.0×1018 cm?3 or more. The average dislocation density of the GaAs wafer is 1500/cm2 or less.
    Type: Application
    Filed: September 27, 2021
    Publication date: December 7, 2023
    Applicant: DOWA Electronics Materials Co., Ltd.
    Inventors: Naoya SUNACHI, Ryuichi TOBA, Akira AKAISHI
  • Patent number: 11819914
    Abstract: A silver powder containing: silver particles; and an adherent that is attached to surfaces of the silver particles and contains a metal oxide that has a melting point lower than a melting point of silver.
    Type: Grant
    Filed: March 24, 2021
    Date of Patent: November 21, 2023
    Assignee: DOWA ELECTRONICS MATERIALS CO., LTD.
    Inventor: Masanori Fujii
  • Patent number: 11804313
    Abstract: Provided is silver powder including silver particles having closed pores inside the particles, wherein when cross sections of the silver particles are observed at a magnification of 10,000, an average of numbers of the pores having Heywood diameters of 200 nm or greater relative to an area of the cross sections is 0.01 pores/?m2 or less, and wherein when the cross sections of the silver particles are observed at a magnification of 40,000, an average of numbers of the pores having Heywood diameters of 10 nm or greater but less than 30 nm relative to the area of the cross sections is 25 pores/?m2 or more.
    Type: Grant
    Filed: September 26, 2019
    Date of Patent: October 31, 2023
    Assignee: Dowa Electronics Materials Co., Ltd.
    Inventors: Masanori Fujii, Yuma Higashi
  • Patent number: 11804567
    Abstract: Provided are a III-nitride semiconductor light-emitting device that can reduce change in the light output power with time and has more excellent light output power, and a method of producing the same. A III-nitride semiconductor light-emitting device 100 has an emission wavelength of 200 nm to 350 nm, and includes an n-type layer 30, a light emitting layer 40, an electron blocking layer 60, and a p-type contact layer 70 in this order. The electron blocking layer 60 has a co-doped region layer 60c, the p-type contact layer 60 is made of p-type AlxGa1-xN (0?x?0.1), and the p-type contact layer 60 has a thickness of 300 nm or more.
    Type: Grant
    Filed: September 25, 2019
    Date of Patent: October 31, 2023
    Assignee: DOWA Electronics Materials Co., Ltd.
    Inventor: Yasuhiro Watanabe
  • Publication number: 20230311249
    Abstract: There is provided a bonding paste capable of forming a uniform bonding layer by reducing occurrence of voids at edges even when a bonding area is large, and bonding method using the paste, and provides a metal paste for bonding containing at least metal nanoparticles (A) having a number average primary particle size of 10 to 100 nm, wherein a cumulative weight loss value (L100) when a temperature is raised from 40° C. to 100° C. is 75 or less, and a cumulative weight loss value (L150) when a temperature is raised from 40° C. to 150° C. is 90 or more, and a cumulative weight loss value (L200) when a temperature is raised from 40° C. to 200° C. is 98 or more, based on 100 cumulative weight loss value (L700) when the paste is heated from 40° C. to 700° C. at a heating rate of 3° C./min in a nitrogen atmosphere.
    Type: Application
    Filed: September 30, 2020
    Publication date: October 5, 2023
    Applicant: DOWA ELECTRONICS MATERIALS CO., LTD.
    Inventors: Keiichi ENDOH, Toshihiko UEYAMA
  • Publication number: 20230279523
    Abstract: There are provided an inexpensive copper powder, which has a low content of oxygen even it has a small particle diameter and which has a high shrinkage starting temperature when it is heated, and a method for producing the same. While a molten metal of copper heated to a temperature, which is higher than the melting point of copper by 250 to 700° C. (preferably 350 to 650° C. and more preferably 450 to 600° C.), is allowed to drop, a high-pressure water is sprayed onto the heated molten metal of copper in a non-oxidizing atmosphere (such as an atmosphere of nitrogen, argon, hydrogen or carbon monoxide) to rapidly cool and solidify the heated molten metal of copper to produce a copper powder which has an average particle diameter of 1 to 10 ?m and a crystallite diameter Dx(200) of not less than 40 nm on (200) plane thereof, the content of oxygen in the copper powder being 0.7% by weight or less.
    Type: Application
    Filed: May 12, 2023
    Publication date: September 7, 2023
    Applicant: Dowa Electronics Materials Co., Ltd.
    Inventors: Masahiro Yoshida, Kenichi Inoue, Atsushi Ebara, Yoshiyuki Michiaki, Takahiro Yamada
  • Publication number: 20230243067
    Abstract: Provided is a GaAs ingot with which a GaAs wafer having a carrier concentration of 5.5×1017 cm?3 or less and low dislocation density with an average dislocation density of 500/cm2 or less can be obtained by adding a small amount of In with Si. A seed side end and a center portion of a straight body part of the GaAs ingot each have a silicon concentration of 2.0×1017 cm?3 or more and less than 1.5×1018 cm?3, an indium concentration of 1.0×1017cm?3 or more and less than 6.5×1018 cm?3, a carrier concentration of 5.5×1017 cm?3 or less, and an average dislocation density of 500/cm2 or less.
    Type: Application
    Filed: June 7, 2021
    Publication date: August 3, 2023
    Applicant: DOWA Electronics Materials Co., Ltd.
    Inventors: Naoya SUNACHI, Ryuichi TOBA, Akira AKAISHI
  • Patent number: 11697863
    Abstract: There are provided a spherical silver powder which has the same diameter as that of a spherical silver powder produced by a conventional wet reduction method and which can sufficiently sinter the silver particles thereof to cause the silver particles to be adhered to each other at a relatively low temperature to form a conductive film having a low volume resistivity when it is used for a baked type conductive paste, and a method for producing the same. A spherical silver powder, which contains a neutral or basic amino acid having a carbon number of not less than 5 in each of particles thereof and which has an average particle diameter D50 of 0.2 to 5 ?m based on a laser diffraction method, is produced by adding the neutral or basic amino acid having the carbon number of not less than 5 (such as proline, tyrosine, tryptophan, phenylalanine, arginine or histidine) to a water reaction system containing silver ions to mix a reducing agent therewith to deposit silver particles by reduction.
    Type: Grant
    Filed: December 13, 2018
    Date of Patent: July 11, 2023
    Assignee: DOWA ELECTRONICS MATERIALS CO., LTD.
    Inventor: Masaya Osako
  • Publication number: 20230216065
    Abstract: A perovskite-type composite oxide powder is a perovskite-type composite oxide powder represented by a general formula ABO3-? (where ? represents an amount of deficiency of oxygen and 0??<1), an element contained in an A site is La, elements contained in a B site are Co and Ni and a crystallite size determined by a Williamson-Hall method is equal to or greater than 20 nm and equal to or less than 100 nm. In this way, when the perovskite-type composite oxide powder is used as an air electrode material for a fuel cell, an air electrode in which the resistance thereof is low and the conductivity thereof is high can be obtained.
    Type: Application
    Filed: July 11, 2020
    Publication date: July 6, 2023
    Applicant: DOWA ELECTRONICS MATERIALS CO., LTD.
    Inventors: Shintaro OGAWA, Kazumasa IKARI, Toshihiko UEYAMA
  • Patent number: 11692241
    Abstract: While a molten metal of copper heated to a temperature, which is higher than the melting point of copper by 250 to 700° C. (preferably 350 to 650° C. and more preferably 450 to 600° C.), is allowed to drop, a high-pressure water is sprayed onto the heated molten metal of copper in a non-oxidizing atmosphere (such as an atmosphere of nitrogen, argon, hydrogen or carbon monoxide) to rapidly cool and solidify the heated molten metal of copper to produce a copper powder which has an average particle diameter of 1 to 10 ?m and a crystallite diameter Dx(200) of not less than 40 nm on (200) plane thereof, the content of oxygen in the copper powder being 0.7% by weight or less.
    Type: Grant
    Filed: December 21, 2017
    Date of Patent: July 4, 2023
    Assignee: DOWA ELECTRONICS MATERIALS CO., LTD.
    Inventors: Masahiro Yoshida, Kenichi Inoue, Atsushi Ebara, Yoshiyuki Michiaki, Takahiro Yamada
  • Publication number: 20230197972
    Abstract: A composite oxide powder including a composition formula (1), wherein the ratio ?/? of a surface area value ?(m2/g) calculated by a BET one-point method to a surface area value ?(m2/g) calculated from a formula (2) is greater than 1.0 and equal to or less than 1.5 and the surface area value ? is equal to or less than 20 m2/g. ABO3-? (1) (wherein A is one or more types of elements (La, Sr, Sm, Ca and Ba), B is one or more types of elements (Fe, Co, Ni and Mn) and 0??<1); and surface area value ?(m2/g)=specific surface area value ?- surface area value ?(2) (the specific surface area value ?(m2/g) is a value in a total pore size range measured by a mercury intrusion method.The specific surface area value ?(m2/g) is a value in a range of pore sizes that are larger than a 50% cumulative particle size.
    Type: Application
    Filed: August 7, 2020
    Publication date: June 22, 2023
    Applicant: DOWA ELECTRONICS MATERIALS CO., LTD.
    Inventors: Kazumasa IKARI, Shintaro OGAWA, Toshihiko UEYAMA
  • Publication number: 20230159376
    Abstract: A silver powder containing: silver particles; and an adherent that is attached to surfaces of the silver particles and contains a metal oxide that has a melting point lower than a melting point of silver.
    Type: Application
    Filed: March 24, 2021
    Publication date: May 25, 2023
    Applicant: DOWA ELECTRONICS MATERIALS CO., LTD.
    Inventor: Masanori FUJII
  • Publication number: 20230155061
    Abstract: Provided is a semiconductor light-emitting element that exhibits a light emission spectrum in which a single peak is obtained by controlling multi peaks. In the semiconductor light-emitting element having a second conductivity type cladding layer on the light extraction side, the arithmetic mean roughness Ra of a surface of the light extraction surface of the second conductivity type cladding layer is 0.07 ?m or more and 0.7 ?m or less, and the skewness Rsk of the surface is a positive value.
    Type: Application
    Filed: October 13, 2020
    Publication date: May 18, 2023
    Applicant: DOWA Electronics Materials Co., Ltd.
    Inventors: Osamu TANAKA, Yoshitaka KADOWAKI
  • Patent number: 11637220
    Abstract: A semiconductor light-emitting element comprises, in this order, a substrate, a reflective layer, a first conductivity type cladding layer made of InGaAsP containing at least In and P, a semiconductor light-emitting layer having an emission central wavelength of 1000 nm to 2200 nm and a second conductivity type cladding layer made of InGaAsP containing at least In and P, the second conductivity type cladding layer being configured to be on a light extraction side, a surface of a light extraction face of the second conductivity type cladding layer being a roughened surface which has a surface roughness Ra of 0.03 ?m or more and has a random irregularity pattern. The surface of the light extraction face has a skewness Rsk of ?1 or more, and a protective film is provided on the light extraction face.
    Type: Grant
    Filed: October 12, 2022
    Date of Patent: April 25, 2023
    Assignee: DOWA Electronics Materials Co., Ltd.
    Inventors: Jumpei Yamamoto, Tetsuya Ikuta
  • Publication number: 20230114703
    Abstract: A semiconductor light-emitting element comprises, in this order, a substrate, a reflective layer, a first conductivity type cladding layer made of InGaAsP containing at least In and P, a semiconductor light-emitting layer having an emission central wavelength of 1000 nm to 2200 nm and a second conductivity type cladding layer made of InGaAsP containing at least In and P, the second conductivity type cladding layer being configured to be on a light extraction side, a surface of a light extraction face of the second conductivity type cladding layer being a roughened surface which has a surface roughness Ra of 0.03 ?m or more and has a random irregularity pattern. The surface of the light extraction face has a skewness Rsk of ?1 or more, and a protective film is provided on the light extraction face.
    Type: Application
    Filed: October 12, 2022
    Publication date: April 13, 2023
    Applicant: DOWA Electronics Materials Co., Ltd.
    Inventors: Jumpei YAMAMOTO, Tetsuya IKUTA