Patents by Inventor Shizuyo Asami
Shizuyo Asami 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).
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Patent number: 6982435Abstract: A group III nitride compound semiconductor device is produced according to the following manner. A separation layer made of a material which prevents group III nitride compound semiconductors from being grown thereon is formed on a substrate. Group III nitride compound semiconductors is grown on a surface of the substrate uncovered with the separation layer while keeping the uncovered substrate surface separated by the separation layer.Type: GrantFiled: November 6, 2001Date of Patent: January 3, 2006Assignee: Toyoda Gosei Co., Ltd.Inventors: Naoki Shibata, Jun Ito, Toshiaki Chiyo, Shizuyo Asami, Hiroshi Watanabe, Shinya Asami
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Patent number: 6939733Abstract: A first group III nitride compound layer, which is formed on a substrate by a method not using metal organic compounds as raw materials, is heated in an atmosphere of a mixture gas containing a hydrogen or nitrogen gas and an ammonia gas, so that the crystallinity of a second group III nitride compound semiconductor layer formed on the first group III nitride compound layer is improved. When the first group III nitride compound layer is formed on a substrate by a sputtering method, the thickness of the first group III nitride compound layer is set to be in a range of from 50 ? to 3000 ?.Type: GrantFiled: December 3, 2003Date of Patent: September 6, 2005Assignee: Toyoda Gosei Co., Ltd.Inventors: Naoki Shibata, Jun Ito, Toshiaki Chiyo, Shizuyo Asami, Hiroshi Watanabe, Masanobu Senda, Shinya Asami
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Patent number: 6918961Abstract: A group III nitride compound semiconductor device has a substrate and an AlN single crystal layer formed on the substrate. The AlN single crystal layer has a thickness of from 0.5 to 3 ?m and has a substantially flat surface. The half-value width of an X-ray rocking curve of the AlN single crystal layer is not longer than 50 sec. In another device, a group III nitride compound semiconductor layer having a thickness of from 0.01 to 3.2 ?m is grown at a temperature of from 1000 to 1180° C. on a sapphire substrate having a surface nitride layer having a thickness of not larger than 300 ?.Type: GrantFiled: April 24, 2003Date of Patent: July 19, 2005Assignee: Toyoda Gosei Co., Ltd.Inventors: Toshiaki Chiyo, Naoki Shibata, Masanobu Senda, Jun Ito, Shizuyo Asami, Shinya Asami, Hiroshi Watanabe
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Patent number: 6872965Abstract: An undercoat layer inclusive of a metal nitride layer is formed on a substrate. Group III nitride compound semiconductor layers are formed on the undercoat layer continuously.Type: GrantFiled: December 18, 2001Date of Patent: March 29, 2005Assignee: Toyoda Gosei Co., Ltd.Inventors: Jun Ito, Toshiaki Chiyo, Naoki Shibata, Hiroshi Watanabe, Shizuyo Asami, Shinya Asami
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Patent number: 6841808Abstract: An AlN layer having a surface of a texture structure is formed on a sapphire substrate. Then, a growth suppressing material layer is formed on the AlN layer so that the AlN layer is partially exposed to the outside. Then, group III nitride compound semiconductor layers are grown on the AlN layer and on the growth suppressing material layer by execution of an epitaxial lateral overgrowth method. Thus, a group III nitride compound semiconductor device is produced. An undercoat layer having convex portions each shaped like a truncated hexagonal pyramid is formed on a substrate. Group III nitride compound semiconductor layers having a device function are laminated successively on the undercoat layer.Type: GrantFiled: June 21, 2001Date of Patent: January 11, 2005Assignee: Toyoda Gosei Co., Ltd.Inventors: Naoki Shibata, Toshiaki Chiyo, Masanobu Senda, Jun Ito, Hiroshi Watanabe, Shinya Asami, Shizuyo Asami
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Patent number: 6830949Abstract: A preferred condition for forming a Group III nitride compound semiconductor layer on a substrate by a sputtering method is proposed. When a first Group III nitride compound semiconductor layer is formed on a substrate by a sputtering method, an initial voltage of a sputtering apparatus is selected to be not higher than 110% of a sputtering voltage.Type: GrantFiled: October 21, 2002Date of Patent: December 14, 2004Assignee: Toyoda Gosei Co., Ltd.Inventors: Masanobu Senda, Jun Ito, Toshiaki Chiyo, Naoki Shibata, Shizuyo Asami
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Publication number: 20040115917Abstract: A first group III nitride compound layer, which is formed on a substrate by a method not using metal organic compounds as raw materials, is heated in an atmosphere of a mixture gas containing a hydrogen or nitrogen gas and an ammonia gas, so that the crystallinity of a second group III nitride compound semiconductor layer formed on the first group III nitride compound layer is improved. When the first group III nitride compound layer is formed on a substrate by a sputtering method, the thickness of the first group III nitride compound layer is set to be in a range of from 50 Å to 3000 Å.Type: ApplicationFiled: December 3, 2003Publication date: June 17, 2004Applicant: Toyoda Gosei Co., Ltd.Inventors: Naoki Shibata, Jun Ito, Toshiaki Chiyo, Shizuyo Asami, Hiroshi Watanabe, Masanobu Senda, Shinya Asami
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Patent number: 6713789Abstract: A first group III nitride compound layer, which is formed on a substrate by a method not using metal organic compounds as raw materials, is heated in an atmosphere of a mixture gas containing a hydrogen or nitrogen gas and an ammonia gas, so that the crystallinity of a second group III nitride compound semiconductor layer formed on the first group III nitride compound layer is improved. When the first group III nitride compound layer is formed on a substrate by a sputtering method, the thickness of the first group III nitride compound layer is set to be in a range of from 50 Å to 3000 Å.Type: GrantFiled: March 1, 2000Date of Patent: March 30, 2004Assignee: Toyoda Gosei Co., Ltd.Inventors: Naoki Shibata, Jun Ito, Toshiaki Chiyo, Shizuyo Asami, Hiroshi Watanabe, Masanobu Senda, Shinya Asami
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Publication number: 20030205195Abstract: A group III nitride compound semiconductor device has a substrate and an AlN single crystal layer formed on the substrate. The AlN single crystal layer has a thickness of from 0.5 to 3 &mgr;m and has a substantially flat surface. The half-value width of an X-ray rocking curve of the AlN single crystal layer is not longer than 50 sec. In another device, a group III nitride compound semiconductor layer having a thickness of from 0.01 to 3.2 &mgr;m is grown at a temperature of from 1000 to 1180° C. on a sapphire substrate having a surface nitride layer having a thickness of not larger than 300 Å.Type: ApplicationFiled: April 24, 2003Publication date: November 6, 2003Applicant: TOYODA GOSEI CO., LTD.Inventors: Toshiaki Chiyo, Naoki Shibata, Masanobu Senda, Jun Ito, Shizuyo Asami, Shinya Asami, Hiroshi Watanabe
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Patent number: 6623998Abstract: A method of manufacturing a group III nitride compound semiconductor device, includes providing a substrate, forming a group III nitride compound semiconductor layer having a device function, and forming an undercoat layer between the substrate and the group III nitride semiconductor layer, the undercoat layer having a surface of a peak and trough structure.Type: GrantFiled: November 26, 2002Date of Patent: September 23, 2003Assignee: Toyoda Gosei Co., Ltd.Inventors: Naoki Shibata, Toshiaki Chiyo, Masanobu Senda, Jun Ito, Hiroshi Watanabe, Shinya Asami, Shizuyo Asami
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Patent number: 6593016Abstract: A group III nitride compound semiconductor device has a substrate and an AlN single crystal layer formed on the substrate. The AlN single crystal layer has a thickness of from 0.5 to 3 &mgr;m and has a substantially flat surface. The half-value width of an X-ray rocking curve of the AlN single crystal layer is not longer than 50 sec. In another device, a group III nitride compound semiconductor layer having a thickness of from 0.01 to 3.2 &mgr;m is grown at a temperature of from 1000 to 1180° C. on a sapphire substrate having a surface nitride layer having a thickness of not larger than 300 Å.Type: GrantFiled: June 29, 2000Date of Patent: July 15, 2003Assignee: Toyoda Gosei Co., Ltd.Inventors: Toshiaki Chiyo, Naoki Shibata, Masanobu Senda, Jun Ito, Shizuyo Asami, Shinya Asami, Hiroshi Watanabe
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Publication number: 20030109076Abstract: A preferred condition for forming a Group III nitride compound semiconductor layer on a substrate by a sputtering method is proposed. When a first Group III nitride compound semiconductor layer is formed on a substrate by a sputtering method, an initial voltage of a sputtering apparatus is selected to be not higher than 110% of a sputtering voltage.Type: ApplicationFiled: October 21, 2002Publication date: June 12, 2003Inventors: Masanobu Senda, Jun Ito, Toshiaki Chiyo, Naoki Shibata, Shizuyo Asami
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Publication number: 20030085411Abstract: A group III nitride compound semiconductor device has a substrate, a group III nitride compound semiconductor layer having a device function, and an undercoat layer formed between the substrate and the group III nitride semiconductor layer. The undercoat layer has a surface which has a texture structure, or which is trapezoid shaped in section or which is pit shaped. In addition, a reflection layer made of nitride of at least one metal selected from the group consisting of titanium, zirconium, hafnium and tantalum may be formed on a surface of the undercoat layer. Also the surface of the reflection layer is formed as a texture structure, a trapezoid shape in section or a pit shape.Type: ApplicationFiled: November 26, 2002Publication date: May 8, 2003Applicant: TOYODA GOSEI CO., LTD.Inventors: Naoki Shibata, Toshiaki Chiyo, Masanobu Senda, Jun Ito, Hiroshi Watanabe, Shinya Asami, Shizuyo Asami
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Patent number: 6531719Abstract: A group III nitride compound semiconductor device has a substrate, a group III nitride compound semiconductor layer having a device function, and an undercoat layer formed between the substrate and the group III nitride semiconductor layer. The undercoat layer has a surface which has a texture structure, or which is trapezoid shaped in section or which is pit shaped. In addition, a reflection layer made of nitride of at least one metal selected from the group consisting of titanium, zirconium, hafnium and tantalum may be formed on a surface of the undercoat layer. Also the surface of the reflection layer is formed as a texture structure, a trapezoid shape in section or a pit shape.Type: GrantFiled: June 26, 2001Date of Patent: March 11, 2003Assignee: Toyoda Gosei Co., Ltd.Inventors: Naoki Shibata, Toshiaki Chiyo, Masanobu Senda, Jun Ito, Hiroshi Watanabe, Shinya Asami, Shizuyo Asami
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Publication number: 20030042505Abstract: An undercoat layer inclusive of a metal nitride layer is formed on a substrate. Group III nitride compound semiconductor layers are formed on the undercoat layer continuously.Type: ApplicationFiled: December 18, 2001Publication date: March 6, 2003Applicant: TOYODA GOSEI CO., LTD.Inventors: Jun Ito, Toshiaki Chiyo, Naoki Shibata, Hiroshi Watanabe, Shizuyo Asami, Shinya Asami
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Patent number: 6426512Abstract: An undercoat layer inclusive of a metal nitride layer is formed on a substrate. Group III nitride compound semiconductor layers are formed on the undercoat layer continuously.Type: GrantFiled: March 3, 2000Date of Patent: July 30, 2002Assignee: Toyoda Gosei Co., Ltd.Inventors: Jun Ito, Toshiaki Chiyo, Naoki Shibata, Hiroshi Watanabe, Shizuyo Asami, Shinya Asami
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Publication number: 20020070383Abstract: A group III nitride compound semiconductor device is produced according to the following manner. A separation layer made of a material which prevents group III nitride compound semiconductors from being grown thereon is formed on a substrate. Group III nitride compound semiconductors is grown on a surface of the substrate uncovered with the separation layer while keeping the uncovered substrate surface separated by the separation layer.Type: ApplicationFiled: November 6, 2001Publication date: June 13, 2002Inventors: Naoki Shibata, Jun Ito, Toshiaki Chiyo, Shizuyo Asami, Hiroshi Watanabe, Shinya Asami
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Publication number: 20020014629Abstract: An AlN layer having a surface of a texture structure is formed on a sapphire substrate. Then, a growth suppressing material layer is formed on the AlN layer so that the AlN layer is partially exposed to the outside. Then, group III nitride compound semiconductor layers are grown on the AlN layer and on the growth suppressing material layer by execution of an epitaxial lateral overgrowth method. Thus, a group III nitride compound semiconductor device is produced. An undercoat layer having convex portions each shaped like a truncated hexagonal pyramid is formed on a substrate. Group III nitride compound semiconductor layers having a device function are laminated successively on the undercoat layer.Type: ApplicationFiled: June 21, 2001Publication date: February 7, 2002Inventors: Naoki Shibata, Toshiaki Chiyo, Masanobu Senda, Jun Ito, Hiroshi Watanabe, Shinya Asami, Shizuyo Asami
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Patent number: 6342404Abstract: A group III nitride compound semiconductor device is produced according to the following manner. A separation layer made of a material which prevents group III nitride compound semiconductors from being grown thereon is formed on a substrate. Group III nitride compound semiconductors is grown on a surface of the substrate uncovered with the separation layer while keeping the uncovered substrate surface separated by the separation layer.Type: GrantFiled: March 10, 2000Date of Patent: January 29, 2002Assignee: Toyoda Gosei Co., Ltd.Inventors: Naoki Shibata, Jun Ito, Toshiaki Chiyo, Shizuyo Asami, Hiroshi Watanabe, Shinya Asami
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Publication number: 20010050376Abstract: A group III nitride compound semiconductor device has a substrate, a group III nitride compound semiconductor layer having a device function, and an undercoat layer formed between the substrate and the group III nitride semiconductor layer. The undercoat layer has a surface which has a texture structure, or which is trapezoid shaped in section or which is pit shaped. In addition, a reflection layer made of nitride of at least one metal selected from the group consisting of titanium, zirconium, hafnium and tantalum may be formed on a surface of the undercoat layer. Also the surface of the reflection layer is formed as a texture structure, a trapezoid shape in section or a pit shape.Type: ApplicationFiled: June 26, 2001Publication date: December 13, 2001Applicant: TOYODA GOSEI CO., LTDInventors: Naoki Shibata, Toshiaki Chiyo, Masanobu Senda, Jun Ito, Hiroshi Watanabe, Shinya Asami, Shizuyo Asami