Patents by Inventor Haruhito SAKAI

Haruhito SAKAI 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: 11575068
    Abstract: A method of manufacturing a semiconductor light emitting element includes: forming an active layer made of an aluminum gallium nitride (AlGaN)-based semiconductor material on an n-type clad layer made of an n-type AlGaN-based semiconductor material; removing a portion of each of the active layer and the n-type clad layer by dry etching to expose a portion of the n-type clad layer; forming a first metal layer including titanium (Ti) on an exposed surface of the n-type clad layer; forming a second metal layer including aluminum (Al) on the first metal layer; and forming an n-side electrode by annealing the first metal layer and the second metal layer at a temperature not lower than 560° C. and not higher than 650° C. A film density of the second metal layer before the annealing is lower than 2.7 g/cm3.
    Type: Grant
    Filed: April 24, 2020
    Date of Patent: February 7, 2023
    Assignee: NIKKISO CO., LTD.
    Inventors: Noritaka Niwa, Tetsuhiko Inazu, Haruhito Sakai
  • Patent number: 11355670
    Abstract: A deep ultraviolet light emitting device includes: a light extraction surface; an n-type semiconductor layer provided on the light extraction surface; an active layer having a band gap of 3.4 eV or larger; and a p-type semiconductor layer provided on the active layer. Deep ultraviolet light emitted by the active layer is output outside from the light extraction surface. A side surface of the active layer is inclined with respect to an interface between the n-type semiconductor layer and the active layer, and an angle of inclination of the side surface is not less than 15° and not more than 50°.
    Type: Grant
    Filed: October 29, 2018
    Date of Patent: June 7, 2022
    Assignee: NIKKISO CO., LTD.
    Inventors: Haruhito Sakai, Noritaka Niwa, Tetsuhiko Inazu, Cyril Pernot
  • Patent number: 11322656
    Abstract: A semiconductor light emitting element includes: an n-type clad layer of an n-type aluminum gallium nitride (AlGaN)-based semiconductor material; an active layer of an AlGaN-based semiconductor material provided on a first top surface of the n-type clad layer; and an n-side electrode provided on a second top surface of the n-type clad layer adjacent to the first top surface. The n-side electrode includes a first metal layer on the second top surface containing titanium (Ti) and a second metal layer on the first metal layer containing aluminum (Al). A root-mean-square roughness (Rq) of a top surface of the second metal layer is 5 nm or less.
    Type: Grant
    Filed: May 4, 2020
    Date of Patent: May 3, 2022
    Assignee: NIKKISO CO., LTD.
    Inventors: Haruhito Sakai, Noritaka Niwa, Tetsuhiko Inazu
  • Publication number: 20200266320
    Abstract: A semiconductor light emitting element includes: an n-type clad layer of an n-type aluminum gallium nitride (AlGaN)-based semiconductor material; an active layer of an AlGaN-based semiconductor material provided on a first top surface of the n-type clad layer; and an n-side electrode provided on a second top surface of the n-type clad layer adjacent to the first top surface. The n-side electrode includes a first metal layer on the second top surface containing titanium (Ti) and a second metal layer on the first metal layer containing aluminum (Al). A root-mean-square roughness (Rq) of a top surface of the second metal layer is 5 nm or less.
    Type: Application
    Filed: May 4, 2020
    Publication date: August 20, 2020
    Inventors: Haruhito SAKAI, Noritaka NIWA, Tetsuhiko INAZU
  • Publication number: 20200251611
    Abstract: A method of manufacturing a semiconductor light emitting element includes: forming an active layer made of an aluminum gallium nitride (AlGaN)-based semiconductor material on an n-type clad layer made of an n-type AlGaN-based semiconductor material; removing a portion of each of the active layer and the n-type clad layer by dry etching to expose a portion of the n-type clad layer; forming a first metal layer including titanium (Ti) on an exposed surface of the n-type clad layer; forming a second metal layer including aluminum (Al) on the first metal layer; and forming an n-side electrode by annealing the first metal layer and the second metal layer at a temperature not lower than 560° C. and not higher than 650° C. A film density of the second metal layer before the annealing is lower than 2.7 g/cm3.
    Type: Application
    Filed: April 24, 2020
    Publication date: August 6, 2020
    Inventors: Noritaka NIWA, Tetsuhiko INAZU, Haruhito SAKAI
  • Patent number: 10720547
    Abstract: A method of manufacturing a semiconductor light emitting device includes: forming an active layer of an aluminum gallium nitride (AlGaN)-based semiconductor material on an n-type clad layer of an n-type AlGaN-based semiconductor material; forming a p-type semiconductor layer on the active layer; removing portions of the p-type semiconductor layer, the active layer, and the n-type clad layer so as to expose a partial region of the n-type clad layer; and forming an n-side electrode on the partial region of the n-type clad layer exposed. The removing includes first dry-etching performed by using both a reactive gas and an inert gas and second dry-etching performed after the first dry-etching by using a reactive gas.
    Type: Grant
    Filed: May 24, 2019
    Date of Patent: July 21, 2020
    Assignee: NIKKISO CO., LTD.
    Inventors: Haruhito Sakai, Noritaka Niwa, Tetsuhiko Inazu
  • Publication number: 20190280149
    Abstract: A method of manufacturing a semiconductor light emitting device includes: forming an active layer of an aluminum gallium nitride (AlGaN)-based semiconductor material on an n-type clad layer of an n-type AlGaN-based semiconductor material; forming a p-type semiconductor layer on the active layer; removing portions of the p-type semiconductor layer, the active layer, and the n-type clad layer so as to expose a partial region of the n-type clad layer; and forming an n-side electrode on the partial region of the n-type clad layer exposed. The removing includes first dry-etching performed by using both a reactive gas and an inert gas and second dry-etching performed after the first dry-etching by using a reactive gas.
    Type: Application
    Filed: May 24, 2019
    Publication date: September 12, 2019
    Inventors: Haruhito SAKAI, Noritaka NIWA, Tetsuhiko INAZU
  • Publication number: 20190067520
    Abstract: A deep ultraviolet light emitting device includes: a light extraction surface; an n-type semiconductor layer provided on the light extraction surface; an active layer having a band gap of 3.4 eV or larger; and a p-type semiconductor layer provided on the active layer. Deep ultraviolet light emitted by the active layer is output outside from the light extraction surface. A side surface of the active layer is inclined with respect to an interface between the n-type semiconductor layer and the active layer, and an angle of inclination of the side surface is not less than 15° and not more than 50°.
    Type: Application
    Filed: October 29, 2018
    Publication date: February 28, 2019
    Inventors: Haruhito SAKAI, Noritaka NIWA, Tetsuhiko INAZU, Cyril PERNOT