Patents by Inventor Yasushi Ogata

Yasushi Ogata 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: 7709837
    Abstract: Nickel is selectively held in contact with a particular region of an amorphous silicon film. Crystal growth parallel with a substrate is effected by performing a heat treatment. A thermal oxidation film is formed on the silicon film by performing a heat treatment in an oxidizing atmosphere containing a halogen element. During this step, in the silicon film, impurities included such as oxygen or chlorine, are segregated with extending along the crystal growth, the crystallinity is improved, and the gettering of nickel element proceeds. A thin-film transistor is formed so that the direction connecting source and drain regions coincides with the above crystal growth direction. As a result, a TFT having superior characteristics such as a mobility larger than 200 cm2/Vs and an S value smaller than 100 mV/dec. can be obtained.
    Type: Grant
    Filed: July 10, 2006
    Date of Patent: May 4, 2010
    Assignee: Semiconductor Energy Laboratory Co., Ltd
    Inventors: Shunpei Yamazaki, Satoshi Teramoto, Jun Koyama, Yasushi Ogata, Masahiko Hayakawa, Mitsuaki Osame, Hisashi Ohtani, Toshiji Hamatani
  • Patent number: 7679087
    Abstract: There is disclosed a method of fabricating a thin-film transistor having excellent characteristics. Nickel element is held in contact with selected regions of an amorphous silicon film. Then, thermal processing is performed to crystallize the amorphous film. Subsequently, thermal processing is carried out in an oxidizing ambient containing a halogen element to form a thermal oxide film. At this time, the crystallinity is improved. Also, gettering of the nickel element proceeds. This crystalline silicon film consists of crystals grown radially from a number of points. Consequently, the thin-film transistor having excellent characteristics can be obtained.
    Type: Grant
    Filed: August 9, 2002
    Date of Patent: March 16, 2010
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Shunpei Yamazaki, Satoshi Teramoto, Jun Koyama, Yasushi Ogata, Masahiko Hayakawa, Mitsuaki Osame, Hisashi Ohtani, Toshiji Hamatani
  • Publication number: 20090231533
    Abstract: A wiring line is electrically connected in parallel to an auxiliary wiring line via a plurality of contact holes. The contact holes are formed through an insulating film and arranged in vertical direction to the wiring line. Since the auxiliary wiring line is formed in the same layer as an electrode that constitutes a TFT, the electric resistance of the wiring line can be reduced effectively without increasing the number of manufacturing steps.
    Type: Application
    Filed: May 28, 2009
    Publication date: September 17, 2009
    Applicant: SEMICONDUCTOR ENERGY LABORATORY CO., LTD.
    Inventors: Jun Koyama, Hisashi Ohtani, Yasushi Ogata, Shunpei Yamazaki
  • Patent number: 7550325
    Abstract: A wiring line is electrically connected in parallel to an auxiliary wiring line via a plurality of contact holes. The contact holes are formed through an insulating film and arranged in vertical direction to the wiring line. Since the auxiliary wiring line is formed in the same layer as an electrode that constitutes a TFT, the electric resistance of the wiring line can be reduced effectively without increasing the number of manufacturing steps.
    Type: Grant
    Filed: July 17, 2003
    Date of Patent: June 23, 2009
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Jun Koyama, Hisashi Ohtani, Yasushi Ogata, Shunpei Yamazaki
  • Publication number: 20090134395
    Abstract: A first insulating thin film having a large dielectric constant such as a silicon nitride film is formed so as to cover a source line and a metal wiring that is in the same layer as the source line. A second insulating film that is high in flatness is formed on the first insulating film. An opening is formed in the second insulating film by etching the second insulating film, to selectively expose the first insulating film. A conductive film to serve as a light-interruptive film is formed on the second insulating film and in the opening, whereby an auxiliary capacitor of the pixel is formed between the conductive film and the metal wiring with first the insulating film serving as a dielectric. The effective aperture ratio can be increased by forming the auxiliary capacitor in a selected region where the influences of alignment disorder of liquid crystal molecules, i.e., disclination, are large.
    Type: Application
    Filed: January 23, 2009
    Publication date: May 28, 2009
    Applicant: SEMICONDUCTOR ENERGY LABORATORY CO., LTD.
    Inventors: Hisashi OHTANI, Yasushi OGATA
  • Patent number: 7483089
    Abstract: A first insulating thin film having a large dielectric constant such as a silicon nitride film is formed so as to cover a source line and a metal wiring that is in the same layer as the source line. A second insulating film that is high in flatness is formed on the first insulating film. An opening is formed in the second insulating film by etching the second insulating film, to selectively expose the first insulating film. A conductive film to serve as a light-interruptive film is formed on the second insulating film and in the opening, whereby an auxiliary capacitor of the pixel is formed between the conductive film and the metal wiring with first the insulating film serving as a dielectric. The effective aperture ratio can be increased by forming the auxiliary capacitor in a selected region where the influences of alignment disorder of liquid crystal molecules, i.e., disclination, are large.
    Type: Grant
    Filed: December 2, 2002
    Date of Patent: January 27, 2009
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Hisashi Ohtani, Yasushi Ogata
  • Publication number: 20090015743
    Abstract: An conductive coating serves as a light shield film and is kept at a given voltage. A metal interconnection is located in the same layer as a source line and connected to the drain of a thin-film transistor. An interlayer insulating film is constituted of at least lower and upper insulating layers and formed between the conductive coating and the source line. According to one aspect of the invention, an auxiliary capacitor is formed by the metal interconnection and the conductive coating serving as both electrodes and at least the lower insulating layer film serving as a dielectric. The auxiliary capacitor is formed in a region of the interlayer insulating film in which the upper insulating layer has been removed by etching. According to another aspect of the invention, the conductive coating has a portion that is in contact with the lower insulating layer in a region where the conductive coating coextends with the metal interconnection.
    Type: Application
    Filed: July 7, 2008
    Publication date: January 15, 2009
    Applicant: SEMICONDUCTOR ENERGY LABORATORY CO., LTD.
    Inventors: Hisashi Ohtani, Yasushi Ogata, Yoshiharu Hirakata
  • Patent number: 7456056
    Abstract: A novel and very useful method for forming a crystal silicon film by introducing a metal element which promotes crystallization of silicon to an amorphous silicon film and for eliminating or reducing the metal element existing within the crystal silicon film thus obtained is provided. The method for fabricating a semiconductor device comprises steps of intentionally introducing the metal element which promotes crystallization of silicon to the amorphous silicon film and crystallizing the amorphous silicon film by a first heat treatment to obtain the crystal silicon film; eliminating or reducing the metal element existing within the crystal silicon film by implementing a second heat treatment within an oxidizing atmosphere; eliminating a thermal oxide film formed in the previous step; and forming another thermal oxide film on the surface of the region from which the thermal oxide film has been eliminated by implementing another thermal oxidation.
    Type: Grant
    Filed: November 6, 2002
    Date of Patent: November 25, 2008
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Shunpei Yamazaki, Satoshi Teramoto, Jun Koyama, Yasushi Ogata, Masahiko Hayakawa, Mitsuaki Osame, Hisashi Ohtani, Toshiji Hamatani
  • Patent number: 7427780
    Abstract: There is disclosed a method of fabricating a thin-film transistor having excellent characteristics. Nickel element is held in contact with selected regions of an amorphous silicon film. Then, thermal processing is performed to crystallize the amorphous film. Subsequently, thermal processing is carried out in an oxidizing ambient containing a halogen element to form a thermal oxide film. At this time, the crystallinity is improved. Also, gettering of the nickel element proceeds. This crystalline silicon film consists of crystals grown radially from a number of points. Consequently, the thin-film transistor having excellent characteristics can be obtained.
    Type: Grant
    Filed: November 14, 2003
    Date of Patent: September 23, 2008
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Shunpei Yamazaki, Satoshi Teramoto, Jun Koyama, Yasushi Ogata, Masahiko Hayakawa, Mitsuaki Osame, Hisashi Ohtani, Toshiji Hamatani
  • Patent number: 7422630
    Abstract: Concentration of metal element which promotes crystallization of silicon and which exists within a crystal silicon film obtained by utilizing the metal element is reduced. A first heat treatment for crystallization is implemented after introducing nickel to an amorphous silicon film 103. Then, laser light is irradiated to diffuse the nickel element concentrated locally. After that, another heat treatment is implemented within an oxidizing atmosphere at a temperature higher than that of the previous heat treatment. A thermal oxide film 106 is formed in this step. At this time, the nickel element is gettered to the thermal oxide film 106. Then, the thermal oxide film 106 is removed. Thereby, a crystal silicon film 107 having low concentration of the metal element and a high crystallinity can be obtained.
    Type: Grant
    Filed: June 5, 2006
    Date of Patent: September 9, 2008
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Shunpei Yamazaki, Satoshi Teramoto, Jun Koyama, Yasushi Ogata, Masahiko Hayakawa, Mitsuaki Osame
  • Patent number: 7397518
    Abstract: An conductive coating serves as a light shield film and is kept at a give voltage. A metal interconnection is located in the same layer as a source line and connected to the drain of a thin-film transistor. An interlayer insulating film is constituted of at least lower and upper insulating layers and formed between the conductive coating and the source line. According to one aspect of the invention, an auxiliary capacitor is formed by the metal interconnection and the conductive coating serving as both electrodes and at least the lower insulating layer film serving as a dielectric. The auxiliary capacitor is formed in a region of the interlayer insulating film in which the upper insulating layer has been removed by etching. According to another aspect of the invention, the conductive coating has a portion that is in contact with the lower insulating layer in a region where the conductive coating coextends with the metal interconnection.
    Type: Grant
    Filed: June 6, 2000
    Date of Patent: July 8, 2008
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Hisashi Ohtani, Yasushi Ogata, Yoshiharu Hirakata
  • Publication number: 20080087894
    Abstract: After an amorphous semiconductor thin film is crystallized by utilizing a catalyst element, the catalyst element is removed by performing a heat treatment in an atmosphere containing a halogen element. A resulting crystalline semiconductor thin film exhibits {110} orientation. Since individual crystal grains have approximately equal orientation, the crystalline semiconductor thin film has substantially no grain boundaries and has such crystallinity as to be considered a single crystal or considered so substantially.
    Type: Application
    Filed: November 19, 2007
    Publication date: April 17, 2008
    Applicant: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Shunpei Yamazaki, Hisashi Ohtani, Toru Mitsuki, Akiharu Miyanaga, Yasushi Ogata
  • Patent number: 7348956
    Abstract: In a peripheral driver circuit of a liquid crystal electro-optical device is comprised of a shift register circuit arranged by a plurality of registers, and a circuit for supplying power to each register. When an input signal is entered into an nth register, a supply of power to at least a portion of registers other than the nth register is stopped. The shift register circuit is constructed of a P-channel type TFT and a resistor. The circuit for supplying the power controls the supply of power to the shift register by using the output of the shift register circuit. This circuit for supplying the power is arranged by a P-channel type TFT and a resistor. The consumption power of the circuit for supplying the power is equal to and lower than that of the shift register circuit.
    Type: Grant
    Filed: October 6, 2006
    Date of Patent: March 25, 2008
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Jun Koyama, Yasushi Ogata, Shunpei Yamazaki
  • Patent number: 7323717
    Abstract: A wiring line to which a high-frequency signal is applied is electrically connected in parallel to an auxiliary, wiring line via a plurality of contact holes. The contact holes are formed through an interlayer insulating film and arranged in vertical direction to the wiring line. Since the auxiliary wiring line is formed in the same layer as an electrode that constitutes a TFT, the electric resistance of the wiring line can be reduced effectively and waveform rounding of an applied high-frequency signal can be reduced without increasing the number of manufacturing steps.
    Type: Grant
    Filed: May 21, 2004
    Date of Patent: January 29, 2008
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Jun Koyama, Hisashi Ohtani, Yasushi Ogata, Shunpei Yamazaki
  • Patent number: 7297978
    Abstract: After an amorphous semiconductor thin film is crystallized by utilizing a catalyst element, the catalyst element is removed by performing a heat treatment in an atmosphere containing a halogen element. A resulting crystalline semiconductor thin film exhibits {110} orientation. Since individual crystal grains have approximately equal orientation, the crystalline semiconductor thin film has substantially no grain boundaries and has such crystallinity as to be considered a single crystal or considered so substantially.
    Type: Grant
    Filed: November 9, 2004
    Date of Patent: November 20, 2007
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Shunpei Yamazaki, Hisashi Ohtani, Toru Mitsuki, Akiharu Miyanaga, Yasushi Ogata
  • Patent number: 7173282
    Abstract: Nickel is selectively held in contact with a particular region of an amorphous silicon film. Crystal growth parallel with a substrate is effected by performing a heat treatment. A thermal oxidation film is formed by performing a heat treatment in an oxidizing atmosphere containing a halogen element. During this step, the crystallinity is improved and the gettering of nickel elements proceeds. A thin-film transistor is formed so that the direction connecting source and drain regions coincides with the above crystal growth direction. As a result, a TFT having superior characteristics such as a mobility larger than 200 cm2/Vs and an S value smaller than 100 mV/dec. can be obtained.
    Type: Grant
    Filed: June 1, 2004
    Date of Patent: February 6, 2007
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Shunpei Yamazaki, Satoshi Teramoto, Jun Koyama, Yasushi Ogata, Masahiko Hayakawa, Mitsuaki Osame, Hisashi Ohtani, Toshiji Hamatani
  • Publication number: 20070024569
    Abstract: In a peripheral driver circuit of a liquid crystal electro-optical device is comprised of a shift register circuit arranged by a plurality of registers, and a circuit for supplying power to each register. When an input signal is entered into an nth register, a supply of power to at least a portion of registers other than the nth register is stopped. The shift register circuit is constructed of a P-channel type TFT and a resistor. The circuit for supplying the power controls the supply of power to the shift register by using the output of the shift register circuit. This circuit for supplying the power is arranged by a P-channel type TFT and a resistor. The consumption power of the circuit for supplying the power is equal to and lower than that of the shift register circuit.
    Type: Application
    Filed: October 6, 2006
    Publication date: February 1, 2007
    Applicant: SEMICONDUCTOR ENERGY LABORATORY CO., LTD.
    Inventors: Jun Koyama, Yasushi Ogata, Shunpei Yamazaki
  • Patent number: 7141491
    Abstract: Concentration of metal element which promotes crystallization of silicon and which exists within a crystalline silicon film obtained by utilizing the metal element is reduced. A first heat treatment for crystallization is performed after introducing nickel to an amorphous silicon film 103. Then, laser light is irradiated to diffuse nickel element which is concentrated locally. After that, another heat treatment is performed within an oxidizing atmosphere at a temperature higher than that of the previous heat treatment. At this time, HCl or the like is added to the atmosphere. A thermal oxide film 106 is formed in this step. At this time, gettering of the nickel element into the thermal oxide film 106 takes place. Then, the thermal oxide film 106 is removed. Thereby, a crystalline silicon film 107 having low concentration of the metal element and a high crystallinity can be obtained.
    Type: Grant
    Filed: December 19, 2005
    Date of Patent: November 28, 2006
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Shunpei Yamazaki, Satoshi Teramoto, Jun Koyama, Yasushi Ogata, Masahiko Hayakawa, Mitsuaki Osame
  • Publication number: 20060249730
    Abstract: Nickel is selectively held in contact with a particular region of an amorphous silicon film. Crystal growth parallel with a substrate is effected by performing a heat treatment. A thermal oxidation film is formed on the silicon film by performing a heat treatment in an oxidizing atmosphere containing a halogen element. During this step, in the silicon film, impurities included such as oxygen or chlorine, are segregated with extending along the crystal growth, the crystallinity is improved, and the gettering of nickel element proceeds. A thin-film transistor is formed so that the direction connecting source and drain regions coincides with the above crystal growth direction. As a result, a TFT having superior characteristics such as a mobility larger than 200 cm2/Vs and an S value smaller than 100 mV/dec. can be obtained.
    Type: Application
    Filed: July 10, 2006
    Publication date: November 9, 2006
    Applicant: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Shunpei Yamazaki, Satoshi Teramoto, Jun Koyama, Yasushi Ogata, Masahiko Hayakawa, Mitsuaki Osame, Hisashi Ohtani, Toshiji Hamatani
  • Publication number: 20060236920
    Abstract: Concentration of metal element which promotes crystallization of silicon and which exists within a crystal silicon film obtained by utilizing the metal element is reduced. A first heat treatment for crystallization is implemented after introducing nickel to an amorphous silicon film 103. Then, laser light is irradiated to diffuse the nickel element concentrated locally. After that, another heat treatment is implemented within an oxidizing atmosphere at a temperature higher than that of the previous heat treatment. A thermal oxide film 106 is formed in this step. At this time, the nickel element is gettered to the thermal oxide film 106. Then, the thermal oxide film 106 is removed. Thereby, a crystal silicon film 107 having low concentration of the metal element and a high crystallinity can be obtained.
    Type: Application
    Filed: June 5, 2006
    Publication date: October 26, 2006
    Applicant: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Shunpei Yamazaki, Satoshi Teramoto, Jun Koyama, Yasushi Ogata, Masahiko Hayakawa, Mitsuaki Osame