Patents by Inventor Shinya Boyama

Shinya Boyama 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: 11916164
    Abstract: A method for manufacturing a light-emitting element includes providing the light-emitting element that includes a light-emitting layer with an emission wavelength of not more than 306 nm and a p-type layer including AlGaInN including Mg as an acceptor, and removing hydrogen in the p-type layer from the light-emitting element by irradiating the light-emitting element with ultraviolet light at a wavelength of not more than 306 nm from outside and treating the light-emitting element with heat in a state in which a reverse voltage, or a forward voltage lower than a threshold voltage of the light-emitting element, or no voltage is applied to the light-emitting element. The removing of hydrogen in the p-type layer from the light-emitting element is performed in a N2 atmosphere at not less than 650° C. or in a N2+O2 atmosphere at not less than 500° C.
    Type: Grant
    Filed: December 29, 2021
    Date of Patent: February 27, 2024
    Assignees: TOYODA GOSEI CO., LTD., MEIJO UNIVERSITY
    Inventors: Yoshiki Saito, Shinya Boyama, Shinichi Matsui, Hiroshi Miwa, Kengo Nagata, Tetsuya Takeuchi, Hisanori Ishiguro
  • Publication number: 20220231189
    Abstract: A method for manufacturing a light-emitting element includes providing the light-emitting element that includes a light-emitting layer with an emission wavelength of not more than 306 nm and a p-type layer including AlGaInN including Mg as an acceptor, and removing hydrogen in the p-type layer from the light-emitting element by irradiating the light-emitting element with ultraviolet light at a wavelength of not more than 306 nm from outside and treating the light-emitting element with heat in a state in which a reverse voltage, or a forward voltage lower than a threshold voltage of the light-emitting element, or no voltage is applied to the light-emitting element. The removing of hydrogen in the p-type layer from the light-emitting element is performed in a N2 atmosphere at not less than 650° C. or in a N2+O2 atmosphere at not less than 500° C.
    Type: Application
    Filed: December 29, 2021
    Publication date: July 21, 2022
    Inventors: Yoshiki Saito, Shinya Boyama, Shinichi Matsui, Hiroshi Miwa, Kengo Nagata, Tetsuya Takeuchi, Hisanori Ishiguro
  • Patent number: 9391237
    Abstract: The present invention provides a Group III nitride semiconductor exhibiting reduced contact resistance. A first p-type contact layer of GaN doped with Mg is formed on a p-type cladding layer, using hydrogen as a carrier gas at a growth temperature of 850° C. to 1,050° C., so as to have a thickness of 10 nm to 300 nm. The Mg concentration is 1×1019/cm3 to 1×1020/cm3. Subsequently, a second p-type contact layer of GaN doped with Mg is formed, using nitrogen instead of hydrogen as a carrier gas at a temperature of 600° C. to 800° C. so as to have a thickness of two monolayers to 100 ?. The Mg concentration is 2×1020/cm3 to 1×1021/cm3.
    Type: Grant
    Filed: March 3, 2015
    Date of Patent: July 12, 2016
    Assignee: Toyoda Gosei Co., Ltd.
    Inventor: Shinya Boyama
  • Publication number: 20150255678
    Abstract: The present invention provides a Group III nitride semiconductor exhibiting reduced contact resistance. A first p-type contact layer of GaN doped with Mg is formed on a p-type cladding layer, using hydrogen as a carrier gas at a growth temperature of 850° C. to 1,050° C., so as to have a thickness of 10 nm to 300 nm. The Mg concentration is 1×1019/cm3 to 1×1020/cm3. Subsequently, a second p-type contact layer of GaN doped with Mg is formed, using nitrogen instead of hydrogen as a carrier gas at a temperature of 600° C. to 800° C. so as to have a thickness of two monolayers to 100 ?. The Mg concentration is 2×1020/cm3 to 1×1021/cm3.
    Type: Application
    Filed: March 3, 2015
    Publication date: September 10, 2015
    Inventor: Shinya BOYAMA
  • Patent number: 8980657
    Abstract: The present invention is a method for producing a light-emitting device whose p contact layer has a p-type conduction and a reduced contact resistance with an electrode. On a p cladding layer, by MOCVD, a first p contact layer of GaN doped with Mg is formed. Subsequently, after lowering the temperature to a growth temperature of a second p contact layer being formed in the subsequent process, which is 700° C., the supply of ammonia is stopped and the carrier gas is switched from hydrogen to nitrogen. Thereby, Mg is activated in the first p contact layer, and the first p contact layer has a p-type conduction. Next, the second p contact layer of InGaN doped with Mg is formed on the first p contact layer by MOCVD using nitrogen as a carrier gas while maintaining the temperature at 700° C. which is the temperature of the previous process.
    Type: Grant
    Filed: July 10, 2012
    Date of Patent: March 17, 2015
    Assignee: Toyoda Gosei Co., Ltd.
    Inventors: Shinya Boyama, Yasuhisa Ushida
  • Patent number: 8546836
    Abstract: A light-emitting element includes a semiconductor laminated structure including a nitride semiconductor, and formed by laminating a first semiconductor layer of a first conductivity type, a light-emitting layer and a second semiconductor layer of a second conductivity type different from the first conductivity type, the first semiconductor layer being exposed by removing a part of the second semiconductor layer and the light-emitting layer, a concave portion formed in the exposed portion of the first semiconductor layer, a first electrode formed on the concave portion and being in ohmic contact with the first semiconductor layer, and a second electrode being in ohmic contact with the second semiconductor layer and formed surrounding the first electrode.
    Type: Grant
    Filed: June 10, 2011
    Date of Patent: October 1, 2013
    Assignee: Toyoda Gosei Co., Ltd.
    Inventors: Masao Kamiya, Shinya Boyama, Yasuhisa Ushida
  • Patent number: 8518806
    Abstract: To produce a Group III nitride-based compound semiconductor having a m-plane main surface and uniformly oriented crystal axes. A mesa having a side surface having an off-angle of 45° or less from c-plane is formed in a a-plane main surface of a sapphire substrate. Subsequently, trimethylaluminum is supplied at 300° C. to 420° C., to thereby form an aluminum layer having a thickness of 40 ? or less. The aluminum layer is nitridated to form an aluminum nitride layer. Through the procedure, a Group III nitride-based compound semiconductor is epitaxially grown only from a side surface of the mesa having an off-angle of 45° or less from c-plane in the sapphire substrate having an a-plane main surface. Thus, a Group III nitride-based compound semiconductor having m-plane which is parallel to the main surface of the sapphire substrate can be formed.
    Type: Grant
    Filed: January 27, 2009
    Date of Patent: August 27, 2013
    Assignee: Toyoda Gosei Co., Ltd.
    Inventors: Koji Okuno, Shugo Nitta, Yoshiki Saito, Yasuhisa Ushida, Naoyuki Nakada, Shinya Boyama
  • Publication number: 20130017639
    Abstract: The present invention is a method for producing a light- emitting device whose p contact layer has a p-type conduction and a reduced contact resistance with an electrode. On a p cladding layer, by MOCVD, a first p contact layer of GaN doped with Mg is formed. Subsequently, after lowering the temperature to a growth temperature of a second p contact layer being formed in the subsequent process, which is 700° C., the supply of ammonia is stopped and the carrier gas is switched from hydrogen to nitrogen. Thereby, Mg is activated in the first p contact layer, and the first p contact layer has a p-type conduction. Next, the second p contact layer of InGaN doped with Mg is formed on the first p contact layer by MOCVD using nitrogen as a carrier gas while maintaining the temperature at 700° C. which is the temperature of the previous process.
    Type: Application
    Filed: July 10, 2012
    Publication date: January 17, 2013
    Applicant: Toyoda Gosei Co., Ltd.
    Inventors: Shinya BOYAMA, Yasuhisa Ushida
  • Publication number: 20120049236
    Abstract: A light-emitting element includes a semiconductor laminated structure including a nitride semiconductor, and formed by laminating a first semiconductor layer of a first conductivity type, a light-emitting layer and a second semiconductor layer of a second conductivity type different from the first conductivity type, the first semiconductor layer being exposed by removing a part of the second semiconductor layer and the light-emitting layer, a concave portion formed in the exposed portion of the first semiconductor layer, a first electrode formed on the concave portion and being in ohmic contact with the first semiconductor layer, and a second electrode being in ohmic contact with the second semiconductor layer and formed surrounding the first electrode.
    Type: Application
    Filed: June 10, 2011
    Publication date: March 1, 2012
    Applicant: TOYODA GOSEI CO., LTD.
    Inventors: Masao Kamiya, Shinya Boyama, Yasuhisa Ushida
  • Publication number: 20100308437
    Abstract: To produce a Group III nitride-based compound semiconductor having a m-plane main surface and uniformly oriented crystal axes. A mesa having a side surface having an off-angle of 45° or less from c-plane is formed in a a-plane main surface of a sapphire substrate. Subsequently, trimethylaluminum is supplied at 300° C. to 420° C., to thereby form an aluminum layer having a thickness of 40 ? or less. The aluminum layer is nitridated to form an aluminum nitride layer. Through the procedure, a Group III nitride-based compound semiconductor is epitaxially grown only from a side surface of the mesa having an off-angle of 45° or less from c-plane in the sapphire substrate having an a-plane main surface. Thus, a Group III nitride-based compound semiconductor having m-plane which is parallel to the main surface of the sapphire substrate can be formed.
    Type: Application
    Filed: January 27, 2009
    Publication date: December 9, 2010
    Inventors: Koji Okuno, Shugo Nitta, Yoshiki Saito, Yasuhisa Ushida, Naoyuki Nakada, Shinya Boyama