Patents by Inventor Seiji Sarayama

Seiji Sarayama 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).

  • Crystal growth method, crystal growth apparatus, group-III nitride crystal and group-III nitride semiconductor device
    Patent number: 7001457
    Abstract: A group-III nitride crystal growth method comprises the steps of: a) preparing a mixed molten liquid of an alkaline material and a substance at least containing a group-III metal; b) causing growth of a group-III nitride crystal from the mixed molten liquid prepared in the step a) and a substance at least containing nitrogen; and c) creating a state in which nitrogen can be introduced into the molten liquid prepared by the step a).
    Type: Grant
    Filed: April 30, 2002
    Date of Patent: February 21, 2006
    Assignee: Ricoh Company, Ltd.
    Inventors: Seiji Sarayama, Hisanori Yamane, Masahiko Shimada, Masafumi Kumano, Hirokazu Iwata, Takashi Araki
  • Crystal growth method, crystal growth apparatus, group-III nitride crystal and group-III nitride semiconductor device
    Patent number: 6949140
    Abstract: A group-III nitride crystal growth method, comprising the steps of: a) preparing a mixed molten liquid of an alkaline metal and a material at least comprising a group-III metal; b) growing a group-III nitride crystal of the group-III metal and nitrogen from the mixed molten liquid and a material at least comprising nitrogen; and c) setting a predetermined crystal growth condition according to a zone defined by a pressure and a temperature in said step b).
    Type: Grant
    Filed: December 3, 2002
    Date of Patent: September 27, 2005
    Assignee: Ricoh Company, Ltd.
    Inventors: Seiji Sarayama, Hirokazu Iwata, Masahiko Shimada, Hisanori Yamane, Masato Aoki
  • Crystal growth method, crystal growth apparatus, group-III nitride crystal and group-III nitride semiconductor device
    Publication number: 20050026318
    Abstract: A crystal growth method, comprising the steps of: a) bringing a nitrogen material into a reaction vessel in which a mixed molten liquid comprising an alkaline metal and a group-III metal; and b) growing a crystal of a group-III nitride using the mixed molten liquid and the nitrogen material brought in by the step a) in the reaction vessel, wherein a provision is made such as to prevent a vapor of the alkaline metal from dispersing out of the reaction vessel.
    Type: Application
    Filed: June 28, 2004
    Publication date: February 3, 2005
    Inventors: Seiji Sarayama, Masahiko Shimada, Hisanori Yamane, Masato Aoki
  • Method of growing group III nitride crystal, group III nitride crystal grown thereby, group III nitride crystal growing apparatus and semiconductor device
    Publication number: 20040226503
    Abstract: A method of growing a group III nitride crystal grows a group III nitride crystal from a solution in which an alkaline metal, a group III metal and nitrogen are dissolved, and includes, in the solution, a material which increases solubility of the nitrogen into the solution.
    Type: Application
    Filed: January 28, 2004
    Publication date: November 18, 2004
    Inventors: Hirokazu Iwata, Seiji Sarayama, Hisanori Yamane, Masahiko Shimada, Masato Aoki
  • Crystal growth method, crystal growth apparatus, group-III nitride crystal and group-III nitride semiconductor device
    Patent number: 6780239
    Abstract: A crystal growth method, comprising the steps of: a) bringing a nitrogen material into a reaction vessel in which a mixed molten liquid comprising an alkaline metal and a group-III metal; and b) growing a crystal of a group-III nitride using the mixed molten liquid and the nitrogen material brought in by the step a) in the reaction vessel, wherein a provision is made such as to prevent a vapor of the alkaline metal from dispersing out of the reaction vessel.
    Type: Grant
    Filed: October 16, 2001
    Date of Patent: August 24, 2004
    Assignee: Ricoh Company, Ltd.
    Inventors: Seiji Sarayama, Masahiko Shimada, Hisanori Yamane, Masato Aoki
  • Group III nitride crystal, crystal growth process and crystal growth apparatus of group III nitride
    Publication number: 20040134413
    Abstract: A crystal growth method of a group III nitride includes the steps of forming a melt mixture of an alkali metal and a group III element in a reaction vessel, and growing a crystal of a group III nitride formed of the group III element and nitrogen from the melt mixture in the reaction vessel, wherein the step of growing the crystal of the group III nitride is conducted while controlling an increase rate of degree of supersaturation of a group III nitride component in the melt mixture in a surface region of the melt mixture.
    Type: Application
    Filed: November 7, 2003
    Publication date: July 15, 2004
    Inventors: Hirokazu Iwata, Seiji Sarayama
  • Production of a GaN bulk crystal substrate and a semiconductor device formed on a GaN bulk crystal substrate
    Publication number: 20040031437
    Abstract: A method of making a bulk crystal substrate of a GaN single crystal includes the steps of forming a molten flux of an alkali metal in a reaction vessel and causing a growth of a GaN single crystal from the molten flux, wherein the growth is continued while replenishing a compound containing N from a source outside the reaction vessel.
    Type: Application
    Filed: June 13, 2003
    Publication date: February 19, 2004
    Inventors: Seiji Sarayama, Masahiko Shimada, Hisanori Yamane, Hirokazu Iwata
  • Crystal growth method, crystal growth apparatus, group-III nitride crystal and group-III nitride semiconductor device
    Publication number: 20030164138
    Abstract: A group-III nitride crystal growth method, comprising the steps of: a) preparing a mixed molten liquid of an alkaline metal and a material at least comprising a group-III metal; b) growing a group-III nitride crystal of the group-III metal and nitrogen from the mixed molten liquid and a material at least comprising nitrogen; and c) setting a predetermined crystal growth condition according to a zone defined by a pressure and a temperature in said step b).
    Type: Application
    Filed: December 3, 2002
    Publication date: September 4, 2003
    Inventors: Seiji Sarayama, Hirokazu Iwata, Masahiko Shimada, Hisanori Yamane, Masato Aoki
  • Production of a GaN bulk crystal substrate and a semiconductor device formed on a GaN bulk crystal substrate
    Patent number: 6592663
    Abstract: A method of making a bulk crystal substrate of a GaN single crystal includes the steps of forming a molten flux of an alkali metal in a reaction vessel and causing a growth of a GaN single crystal from the molten flux, wherein the growth is continued while replenishing a compound containing N from a source outside the reaction vessel.
    Type: Grant
    Filed: June 8, 2000
    Date of Patent: July 15, 2003
    Assignee: Ricoh Company Ltd.
    Inventors: Seiji Sarayama, Masahiko Shimada, Hisanori Yamane, Hirokazu Iwata
  • Crystal growth method, crystal growth apparatus, group-III nitride crystal and group-III nitride semiconductor device
    Publication number: 20020175338
    Abstract: A group-III nitride crystal growth method comprises the steps of: a) preparing a mixed molten liquid of an alkaline material and a substance at least containing a group-III metal; b) causing growth of a group-III nitride crystal from the mixed molten liquid prepared in the step a) and a substance at least containing nitrogen; and c) creating a state in which nitrogen can be introduced into the molten liquid prepared by the step a).
    Type: Application
    Filed: April 30, 2002
    Publication date: November 28, 2002
    Inventors: Seiji Sarayama, Hisanori Yamane, Masahiko Shimada, Masafumi Kumano, Hirokazu Iwata, Takashi Araki
  • Crystal growth method, crystal growth apparatus, group-III nitride crystal and group-III nitride semiconductor device
    Publication number: 20020046695
    Abstract: A crystal growth method, comprising the steps of: a) bringing a nitrogen material into a reaction vessel in which a mixed molten liquid comprising an alkaline metal and a group-III metal; and b) growing a crystal of a group-III nitride using the mixed molten liquid and the nitrogen material brought in by the step a) in the reaction vessel, wherein a provision is made such as to prevent a vapor of the alkaline metal from dispersing out of the reaction vessel.
    Type: Application
    Filed: October 16, 2001
    Publication date: April 25, 2002
    Inventors: Seiji Sarayama, Masahiko Shimada, Hisanori Yamane, Masato Aoki