Patents by Inventor Toshihiko Shiga
Toshihiko Shiga 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: 10854523Abstract: A semiconductor device according to the present invention includes: a substrate; a heat generating portion provided on the substrate; a cap substrate provided above the substrate so that a hollow portion is provided between the substrate and the cap substrate; and a reflection film provided above the heat generating portion and reflecting a medium wavelength infrared ray. The reflection film reflects the infrared ray radiated to the cap substrate side through the hollow portion due to the temperature increase of the heat generating portion, so that the temperature increase of the cap substrate side can be suppressed. Because of this function, even if mold resin is provided on the cap substrate, increase of the temperature of the mold resin can be suppressed.Type: GrantFiled: October 24, 2016Date of Patent: December 1, 2020Assignee: Mitsubishi Electric CorporationInventors: Koichiro Nishizawa, Yoshitsugu Yamamoto, Katsumi Miyawaki, Shinsuke Watanabe, Toshihiko Shiga
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Publication number: 20200185285Abstract: A semiconductor device according to the present invention includes: a substrate; a heat generating portion provided on the substrate; a cap substrate provided above the substrate so that a hollow portion is provided between the substrate and the cap substrate; and a reflection film provided above the heat generating portion and reflecting a medium wavelength infrared ray. The reflection film reflects the infrared ray radiated to the cap substrate side through the hollow portion due to the temperature increase of the heat generating portion, so that the temperature increase of the cap substrate side can be suppressed. Because of this function, even if mold resin is provided on the cap substrate, increase of the temperature of the mold resin can be suppressed.Type: ApplicationFiled: October 24, 2016Publication date: June 11, 2020Applicant: Mitsubishi Electric CorporationInventors: Koichiro NISHIZAWA, Yoshitsugu YAMAMOTO, Katsumi MIYAWAKI, Shinsuke WATANABE, Toshihiko SHIGA
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Patent number: 9018736Abstract: A semiconductor device includes a substrate having a hexagonal crystalline structure and a (0001) surface, and conductive films on the surface of the substrate. The conductive films include a first conductive film and a second conductive film located above the first conductive film with respect to the surface, wherein the first conductive film has a crystalline structure which does not have a plane that has a symmetry equivalent to the symmetry of atomic arrangement in the surface of the substrate, the second conductive film has a crystalline structure having at least one plane that has a symmetry equivalent to the symmetry of atomic arrangement in the surface of the substrate, and the second conductive film is polycrystalline and has a grain size no larger than 15 ?m.Type: GrantFiled: January 24, 2014Date of Patent: April 28, 2015Assignee: Mitsubishi Electric CorporationInventors: Kazuhiro Maeda, Toshihiko Shiga
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Publication number: 20140319513Abstract: A semiconductor device includes a substrate having a hexagonal crystalline structure and a (0001) surface, and conductive films on the surface of the substrate. The conductive films include a first conductive film and a second conductive film located above the first conductive film with respect to the surface, wherein the first conductive film has a crystalline structure which does not have a plane that has a symmetry equivalent to the symmetry of atomic arrangement in the surface of the substrate, the second conductive film has a crystalline structure having at least one plane that has a symmetry equivalent to the symmetry of atomic arrangement in the surface of the substrate, and the second conductive film is polycrystalline and has a grain size no larger than 15 ?m.Type: ApplicationFiled: January 24, 2014Publication date: October 30, 2014Applicant: Mitsubishi Electric CorporationInventors: Kazuhiro Maeda, Toshihiko Shiga
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Patent number: 8766445Abstract: A semiconductor device includes: a semiconductor substrate; an underlying wiring on the semiconductor substrate; a resin film extending to the semiconductor substrate and the underlying wiring, and having a first opening on the underlying wiring; a first SiN film on the underlying wiring and the resin film, and having a second opening in the first opening; an upper layer wiring on the underlying wiring and part of the resin film; and a second SiN film on the upper layer wiring and the resin film, and joined to the first SiN film on the resin film. The upper layer wiring includes a Ti film, connected to the underlying wiring via the first and second openings, and an Au film on the Ti film. The first and second SiN films circumferentially protect the Ti film.Type: GrantFiled: June 18, 2012Date of Patent: July 1, 2014Assignee: Mitsubishi Electric CorporationInventors: Takayuki Hisaka, Takahiro Nakamoto, Toshihiko Shiga, Koichiro Nishizawa
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Publication number: 20130093061Abstract: A semiconductor device includes: a semiconductor substrate; an underlying wiring on the semiconductor substrate; a resin film extending to the semiconductor substrate and the underlying wiring, and having a first opening on the underlying wiring; a first SiN film on the underlying wiring and the resin film, and having a second opening in the first opening; an upper layer wiring on the underlying wiring and part of the resin film; and a second SiN film on the upper layer wiring and the resin film, and joined to the first SiN film on the resin film. The upper layer wiring includes a Ti film, connected to the underlying wiring via the first and second openings, and an Au film on the Ti film. The first and second SiN films circumferentially protect the Ti film.Type: ApplicationFiled: June 18, 2012Publication date: April 18, 2013Applicant: MITSUBISHI ELECTRIC CORPORATIONInventors: Takayuki HISAKA, Takahiro NAKAMOTO, Toshihiko SHIGA, Koichiro NISHIZAWA
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Patent number: 7879635Abstract: A method for manufacturing a laser diode includes: providing a semiconductor structure in which semiconductor layers are laminated; forming a waveguide ridge in the layers; forming an SiO2 film over the entire surface; forming a second resist pattern covering the SiO2 film in channels adjacent the waveguide ridge such that top surfaces of the second resist pattern in the channels are higher than the top surface of a p-GaN layer in the waveguide ridge and lower than the top surface of the SiO2 film on the top of the waveguide ridge, the second resist pattern exposing the top surface of the SiO2 film on the top of the waveguide ridge; removing the SiO2 film, using the second resist pattern as a mask, to expose the top surface of the p-GaN layer in the waveguide ridge; and forming an electrode layer on the top surface of the p-GaN layer.Type: GrantFiled: July 2, 2007Date of Patent: February 1, 2011Assignee: Mitsubishi Electric CorporationInventors: Toshihiko Shiga, Hitoshi Sakuma
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Patent number: 7851831Abstract: A transistor includes a nitride semiconductor layer and a gate electrode layer. The gate electrode layer includes a tantalum nitride layer on the nitride semiconductor layer. The tantalum nitride layer forms a Schottky junction with the nitride semiconductor layer. The transistor also includes an insulating film on the nitride semiconductor layer. The insulating film surrounds the gate electrode layer. A first portion of the gate electrode layer, in contact with the nitride semiconductor layer, has a higher nitrogen mole fraction than a second portion of the gate electrode layer.Type: GrantFiled: September 24, 2007Date of Patent: December 14, 2010Assignee: Mitsubishi Electric CorporationInventors: Hidetoshi Koyama, Yoshitaka Kamo, Toshihiko Shiga
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Patent number: 7791097Abstract: A nitride semiconductor device includes an n-type GaN substrate with a semiconductor device formed thereon and an n-type electrode which is a metal electrode formed on the rear surface of the GaN substrate. A surface modified layer and a reaction layer are interposed between the GaN substrate and n-type electrode. The surface modified layer serves as a carrier supplying layer, and is formed by causing the rear surface of the GaN substrate to react with a Si-containing plasma to be modified. The reaction layer is generated by partially removing a deposited material deposited on the surface modified layer by cleaning to generate a deposited layer and then causing Ti contained in a first metal layer and the deposited layer to partially react by heat treatment.Type: GrantFiled: July 2, 2007Date of Patent: September 7, 2010Assignee: Mitsubishi Electric CorporationInventors: Kyozo Kanamoto, Katsuomi Shiozawa, Kazushige Kawasaki, Hitoshi Sakuma, Junichi Horie, Toshihiko Shiga, Toshiyuki Oishi
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Patent number: 7714439Abstract: A nitride semiconductor device according to the present invention includes a P-type contact layer and a P-type electrode provided on the P-type contact layer. The P-type electrode includes a AuGa film provided on the P-type contact layer, a Au film provided on the AuGa film, a Pt film 4 provided on the Au film, and a Au film provided on the Pt film. The ratio of the thickness of the AuGa film to the total thickness of the AuGa film and the Au film is not less than 12% but not more than 46%.Type: GrantFiled: August 24, 2007Date of Patent: May 11, 2010Assignee: Mitsubishi Electric CorporationInventors: Katsuomi Shiozawa, Hitoshi Sakuma, Kazushige Kawasaki, Toshihiko Shiga, Toshiyuki Oishi
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Patent number: 7616673Abstract: A semiconductor laser device includes a semiconductor laser body including a resonator and having a front end face and a rear end face facing each other, the resonator being located between the front end face and the rear end face. The front end face emits principal laser light. A reflectance control film is disposed on the front end face or the rear end face of the semiconductor laser body and is made up of either an aluminum oxide film or a five-layer film including the aluminum oxide film disposed such that it is the layer in the five-layer film farthest from the front end face or the rear end face. A silicon oxide film is disposed on the aluminum oxide film of the reflectance control film and has a thickness of 20 nm or less.Type: GrantFiled: May 24, 2006Date of Patent: November 10, 2009Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Hiromasu Matsuoka, Yasuyuki Nakagawa, Toshihiko Shiga
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Patent number: 7598548Abstract: A Schottky electrode including a WNx layer on an n-type GaN layer. A crystal plane of the n-type GaN layer is in contact with a crystal plane of the WNx layer. The crystal plane of the n-type GaN layer is a (0001)-plane, and the crystal plane of the WNx layer is (111)-oriented. The WNx layer may be an electrode layer having an NaCl-type structure including at least one metal selected from the group consisting of zirconium, hafnium, niobium, tantalum, molybdenum and tungsten, and at least one element selected from nitrogen and carbon. Further, the lattice constant of the electrode layer is preferably 0.95 to 1.05 times the a-axis lattice constant of the n-type GaN layer, multiplied by 2(1/2).Type: GrantFiled: December 1, 2005Date of Patent: October 6, 2009Assignee: Mitsubishi Denki Kabushiki KaishaInventor: Toshihiko Shiga
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Patent number: 7569911Abstract: An ohmic electrode is formed by stacking a lower Ti layer, a diffusion preventing layer, an upper Ti layers and a metallic (Au) layer on a p-type GaAs layer. The diffusion preventing layer includes tantalum (Ta) or niobium (Nb). Thus, interdiffusion of Ga and As in the p-type GaAs layer and Au in the metallic layer can be prevented, and variation in resistivity of the ohmic electrode in a high-temperature, high-humidity environment can be suppressed.Type: GrantFiled: April 25, 2006Date of Patent: August 4, 2009Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Toshihiko Shiga, Hitoshi Nakamura, Junji Tanimura
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Publication number: 20080246060Abstract: A transistor includes a nitride semiconductor layer and a gate electrode layer. The gate electrode layer includes a tantalum nitride layer being formed on the nitride semiconductor layer. The tantalum nitride layer forms a Schottky junction with the nitride semiconductor layer. The transistor also includes an insulating film formed on the nitride semiconductor layer. The insulating film surrounds the gate electrode layer. The portion of the gate electrode layer in contact with the nitride semiconductor layer has a higher nitrogen mole fraction than the other portion of the gate electrode layer.Type: ApplicationFiled: September 24, 2007Publication date: October 9, 2008Applicant: MITSUBISHI ELECTRIC CORPORATIONInventors: Hidetoshi Koyama, Yoshitaka Kamo, Toshihiko Shiga
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Publication number: 20080116575Abstract: A nitride semiconductor device according to the present invention includes a P-type contact layer and a P-type electrode provided on the P-type contact layer. The P-type electrode includes a AuGa film provided on the P-type contact layer, a Au film provided on the AuGa film, a Pt film 4 provided on the Au film, and a Au film provided on the Pt film. The ratio of the thickness of the AuGa film to the total thickness of the AuGa film and the Au film is not less than 12% but not more than 46%.Type: ApplicationFiled: August 24, 2007Publication date: May 22, 2008Applicant: MITSUBISHI ELECTRIC CORPORATIONInventors: Katsuomi Shiozawa, Hitoshi Sakuma, Kazushige Kawasaki, Toshihiko Shiga, Toshiyuki Oishi
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Publication number: 20080029777Abstract: A LD (Laser Diode) includes: a laminated semiconductor structure including an active layer, a p-cladding layer, a contact layer, etc. that are sequentially on top of one another on an n-GaN substrate; a waveguide ridge including the contact layer and a portion of the p-cladding layer; a first silicon insulating film covering sidewalls of the waveguide ridge and having an opening that exposes a top of the waveguide ridge; an adhesive layer disposed on the first silicon insulating film, but not in the opening, and on the top of the waveguide ridge, wherein the adhesive layer includes a first adhesive film of Ti; and a p-side electrode over the adhesive layer such that the p-side electrode is in contact with the contact layer at the top of the waveguide ridge, through the opening.Type: ApplicationFiled: July 12, 2007Publication date: February 7, 2008Applicant: MITSUBISHI ELECTRIC CORPORATIONInventor: Toshihiko Shiga
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Publication number: 20080023799Abstract: A nitride semiconductor device includes an n-type GaN substrate with a semiconductor device formed thereon and an n-type electrode which is a metal electrode formed on the rear surface of the GaN substrate. A surface modified layer and a reaction layer are interposed between the GaN substrate and n-type electrode. The surface modified layer serves as a carrier supplying layer, and is formed by causing the rear surface of the GaN substrate to react with a Si-containing plasma to be modified. The reaction layer is generated by partially removing a deposited material deposited on the surface modified layer by cleaning to generate a deposited layer and then causing Ti contained in a first metal layer and the deposited layer to partially react by heat treatment.Type: ApplicationFiled: July 2, 2007Publication date: January 31, 2008Applicant: MITSUBISHI ELECTRIC CORPORATIONInventors: Kyozo KANAMOTO, Katsuomi Shiozawa, Kazushige Kawasaki, Hitoshi Sakuma, Junichi Horie, Toshihiko Shiga, Toshiyuki Oishi
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Publication number: 20080020502Abstract: A method for manufacturing a laser diode includes: providing a semiconductor structure in which semiconductor layers are laminated; forming a waveguide ridge in the layers; forming an SiO2 film over the entire surface; forming a second resist pattern covering the SiO2 film in channels adjacent the waveguide ridge such that top surfaces of the second resist pattern in the channels are higher than the top surface of a p-GaN layer in the waveguide ridge and lower than the top surface of the SiO2 film on the top of the waveguide ridge, the second resist pattern exposing the top surface of the SiO2 film on the top of the waveguide ridge; removing the SiO2 film, using the second resist pattern as a mask, to expose the top surface of the p-GaN layer in the waveguide ridge; and forming an electrode layer on the top surface of the p-GaN layer.Type: ApplicationFiled: July 2, 2007Publication date: January 24, 2008Applicant: MITSUBISHI ELECTRIC CORPORATIONInventors: Toshihiko Shiga, Hitoshi Sakuma
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Patent number: 7288486Abstract: In a method for manufacturing a semiconductor device wherein via holes are formed in an SiC substrate, a stacked film consisting of a Ti film and an Au film is formed on the back face of the SiC substrate, and a Pd film is formed thereon. Then, an Ni film is formed by non-electrolytic plating, using the Pd film as a catalyst. Thereafter, via holes penetrating through the SiC substrate are formed by etching, using the Ni film as a mask.Type: GrantFiled: June 22, 2006Date of Patent: October 30, 2007Assignee: Mitsubishi Electric CorporationInventors: Takeo Shirahama, Toshihiko Shiga, Kouichirou Hori
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Publication number: 20070128852Abstract: In a method for manufacturing a semiconductor device wherein via holes are formed in an SiC substrate, a stacked film consisting of a Ti film and an Au film is formed on the back face of the SiC substrate, and a Pd film is formed thereon. Then, an Ni film is formed by non-electrolytic plating, using the Pd film as a catalyst. Thereafter, via holes penetrating through the SiC substrate are formed by etching, using the Ni film as a mask.Type: ApplicationFiled: June 22, 2006Publication date: June 7, 2007Applicant: Mitsubishi Electric CorporationInventors: Takeo Shirahama, Toshihiko Shiga, Kouichirou Hori