Patents by Inventor Takashi Funai

Takashi Funai 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: 6162667
    Abstract: In a fabrication of a semiconductor device, an amorphous semiconductor film is first formed on a substrate having an insulating surface. Then, a minute amount of catalyst elements for accelerating crystallization of the amorphous semiconductor film is supplied to at least a portion of a surface of the amorphous semiconductor film. A heat treatment is further conducted so that the supplied catalyst elements are diffused into the amorphous semiconductor film. Thus, the catalyst elements are introduced uniformly into the amorphous semiconductor film in a very minute amount or at a low concentration, resulting in polycrystallization of at least a portion of the amorphous semiconductor film. Utilizing the thus obtained crystalline semiconductor film on the substrate surface as an active region, a semiconductor device such as a TFT is fabricated.
    Type: Grant
    Filed: March 23, 1995
    Date of Patent: December 19, 2000
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Takashi Funai, Naoki Makita, Yoshitaka Yamamoto, Tadayoshi Miyamoto, Takamasa Kousai, Masashi Maekawa
  • Patent number: 6010922
    Abstract: The semiconductor device of this invention includes a substrate having an insulating surface and a thin film transistor formed on the substrate, wherein the thin film transistor has a semiconductor island including a channel region and source/drain regions, a gate insulating film formed on the semiconductor island and a gate electrode covering the channel region of the semiconductor island interposing the gate insulating film therebetween, and wherein a distance between an edge of the channel region of the semiconductor island and the gate electrode is larger than a distance between a central portion of the channel region of the semiconductor island and the gate electrode.
    Type: Grant
    Filed: December 22, 1997
    Date of Patent: January 4, 2000
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Akihiro Hata, Takashi Funai, Masahiro Adachi
  • Patent number: 5970327
    Abstract: A semiconductor device comprising a substrate having thereon an amorphous silicon film fabricated by a reduced pressure chemical vapor deposition, characterized in that a thin film transistor is provided by using a crystalline silicon film obtained by effecting crystal growth in parallel with the surface of the substrate at the periphery of a region containing a selectively introduced metallic element, the region being obtained by selectively introducing a metallic element capable of accelerating the crystallization of the amorphous silicon film and heating the region thereafter.
    Type: Grant
    Filed: November 21, 1997
    Date of Patent: October 19, 1999
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Naoki Makita, Takashi Funai, Toru Takayama
  • Patent number: 5851860
    Abstract: The semiconductor device of the invention includes: a substrate having an insulating surface; an active region formed on the insulating surface of the substrate, the active region being formed by a crystalline silicon film; and an insulating thin film formed on the active region. In the semiconductor device, the active region contains a catalyst element for promoting a crystallization of an amorphous silicon film by a heat treatment.
    Type: Grant
    Filed: June 2, 1995
    Date of Patent: December 22, 1998
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Naoki Makita, Takashi Funai
  • Patent number: 5821562
    Abstract: Into an amorphous silicon film, catalyst elements for accelerating the crystallization are introduced. After patterning the amorphous silicon films in which the catalyst elements have been introduced into an island pattern, a heat treatment for the crystallization is conducted. Thus, the introduced catalyst elements efficiently diffuse only inside the island-patterned amorphous silicon films. As a result, a high-quality crystalline silicon film, having the crystal growth direction aligned in one direction and having no grain boundaries, is obtained. Using the thus formed crystalline silicon film, semiconductor devices having a high performance and stable characteristics are fabricated efficiently over the entire substrate, irrespective of the size of the devices.
    Type: Grant
    Filed: May 30, 1995
    Date of Patent: October 13, 1998
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Naoki Makita, Takashi Funai, Yoshitaka Yamamoto, Yasuhiro Mitani, Katsumi Nomura, Tadayoshi Miyamoto, Takamasa Kosai
  • Patent number: 5811327
    Abstract: In a substrate having an insulating surface in which an amorphous semiconductor film is deposited on the insulating surface, a predetermined under-heating portion of the amorphous semiconductor film is partially heated with a heating source emitting heating rays. While heating, the under-heating portion is shifted by moving the heating source or the substrate. Accordingly, the amorphous semiconductor film is sequentially heat-treated and polycrystallized. As the under-heating portion shifts, the polycrystallization sequentially proceeds using the already polycrystallized portion by irradiation with the heating rays, which is adjacent to the under-heating portion, as seed crystal. Thus, the growth condition of crystal grains is uniformly controlled in the shifting direction of the under-heating portion.
    Type: Grant
    Filed: March 21, 1995
    Date of Patent: September 22, 1998
    Assignees: Sharp Kabushiki Kaisha, Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Takashi Funai, Naoki Makita, Toru Takayama
  • Patent number: 5747828
    Abstract: The semiconductor device of this invention includes a substrate having an insulating surface and a thin film transistor formed on the substrate, wherein the thin film transistor has a semiconductor island including a channel region and source/drain regions, a gate insulating film formed on the semiconductor island and a gate electrode covering the channel region of the semiconductor island interposing the gate insulating film therebetween, and wherein a distance between an edge of the channel region of the semiconductor island and the gate electrode is larger then a distance between a central portion of the channel region of the semiconductor island and the gate electrode.
    Type: Grant
    Filed: March 28, 1996
    Date of Patent: May 5, 1998
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Akihiro Hata, Takashi Funai, Masahiro Adachi
  • Patent number: 5696003
    Abstract: Into an amorphous silicon film, catalyst elements for accelerating the crystallization are introduced. After patterning the amorphous silicon films in which the catalyst elements have been introduced into an island pattern, a heat treatment for the crystallization is conducted. Thus, the introduced catalyst elements efficiently diffuse only inside the island-patterned amorphous silicon films. As a result, a high-quality crystalline silicon film, having the crystal growth direction aligned in one direction and having no grain boundaries, is obtained. Using the thus formed crystalline silicon film, semiconductor devices having a high performance and stable characteristics are fabricated efficiently over the entire substrate, irrespective of the size of the devices.
    Type: Grant
    Filed: December 16, 1994
    Date of Patent: December 9, 1997
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Naoki Makita, Takashi Funai, Yoshitaka Yamamoto, Yasuhiro Mitani, Katsumi Nomura, Tadayoshi Miyamoto, Takamasa Kosai
  • Patent number: 5550070
    Abstract: A method for producing a semiconductor film, includes the steps of: (a) forming an amorphous semiconductor film on a substrate having a surface with an insulating property; (b) introducing a material for accelerating crystallization of the amorphous semiconductor film into at least a part of the amorphous semiconductor film; (c) crystallizing the amorphous semiconductor film by heating to obtain a crystalline semiconductor film from the amorphous semiconductor film; and (d) oxidizing a surface of the crystalline semiconductor film to form a semiconductor oxide film containing a part of the material for accelerating the crystallization on the surface of the crystalline semiconductor film.
    Type: Grant
    Filed: December 16, 1994
    Date of Patent: August 27, 1996
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Takashi Funai, Naoki Makita, Yoshitaka Yamamoto, Tatsuo Morita