Patents by Inventor Hongyong Zhang

Hongyong Zhang 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: 5624851
    Abstract: A semiconductor circuit and a process for fabricating the same, said process comprising forming in contact with an amorphous silicon film, a substance containing a catalytic element; crystallizing selected portions of the amorphous silicon film by annealing said film at a temperature lower than the ordinary crystallization temperature of an amorphous silicon film; and then crystallizing the rest of the portions by irradiating thereto laser beam or an intense light having an intensity equivalent thereto. A process similar to the one above, wherein, the catalytic element is incorporated directly into the amorphous silicon film instead of bringing a substance containing the same into contact with the amorphous silicon film.
    Type: Grant
    Filed: March 8, 1994
    Date of Patent: April 29, 1997
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Toru Takayama, Hongyong Zhang, Yasuhiko Takemura
  • Patent number: 5620906
    Abstract: In producing a semiconductor device such as a thin film transistor (TFT), a silicon semiconductor film is formed on a substrate having an insulating surface, such as a glass substrate, and then a silicon nitride film is formed on the silicon semiconductor film. After that, a hydrogen ion, fluorine ion, or chlorine ion is introduced into the silicon semiconductor film through the silicon nitride film, and then the silicon semiconductor film into which an ion is introduced is heated in an atmosphere containing hydrogen, fluorine, chlorine or these mixture, to neutralize dangling bonds in the silicon semiconductor film and reduce levels in the silicon semiconductor film.
    Type: Grant
    Filed: February 28, 1995
    Date of Patent: April 15, 1997
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Naoaki Yamaguchi, Hongyong Zhang, Satoshi Teramoto, Hideto Ohnuma
  • Patent number: 5620905
    Abstract: In a semiconductor integrated circuit, a plurality of thin film transistors (TFTs) are formed on the same substrate having an insulating surface. Since gate electrodes formed in the TFTs are electrically insulated each other, voltages are applied independently to gate electrodes in an electrolytic solution during an anodization, to form an anodic oxide in at least both sides of each gate electrode. A thickness of the anodic oxide is changed in accordance with characteristics of the TFT. A width of high resistance regions formed in an active layer of each TFT is changed by ion doping using the anodic oxide having a desired thickness as a mask.
    Type: Grant
    Filed: March 29, 1995
    Date of Patent: April 15, 1997
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Toshimitsu Konuma, Masaaki Hiroki, Hongyong Zhang, Mutsuo Yamamoto, Yasuhiko Takemura
  • Patent number: 5614733
    Abstract: A semiconductor device has a first thin film transistor and a second thin film transistor formed on a substrate. Both of the first and second thin film transistor have a crystallized channel region. One of the first and second thin film transistor is doped with a catalyst metal at a sufficient concentration for promoting the crystallization of the channel region which the other of the first and second thin film transistors is not doped with the catalyst metal.
    Type: Grant
    Filed: December 12, 1994
    Date of Patent: March 25, 1997
    Assignee: Semiconductor Energy Laboratory Co., Inc.
    Inventors: Hongyong Zhang, Toru Takayama, Yasuhiko Takemura
  • Patent number: 5614426
    Abstract: In an active matrix type liquid-crystal display device, in a peripheral circuit portion, there is arranged a TFT having a high mobility and capable of allowing a large amount of on-state current to flow. In a pixel portion, there is arranged a TFT having a small off-state current. These TFTs having different characteristics are constituted by using crystalline silicon film whose crystal has grown in a direction parallel with a substrate. That is, an angle formed between a crystal growing direction and a carrier moving direction are made different from each other, thereby to control a resistance imposed on the carriers when moving to determine the characteristics of the TFT. For example, when the crystal growing direction coincides with the carrier moving direction, high mobility can be given to the carriers. Further, when the crystal growing direction is arranged perpendicular to the carrier moving direction, the off-state current can be lowered.
    Type: Grant
    Filed: August 23, 1995
    Date of Patent: March 25, 1997
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Fumiaki Funada, Tatsuo Morita, Hirohisa Tanaka, Hongyong Zhang, Toru Takayama
  • Patent number: 5612250
    Abstract: A method for manufacturing a thin film transistor having a crystalline silicon layer as an active layer comprises the steps of disposing a solution containing a catalyst for promoting a crystallization of silicon in contact with an amorphous silicon film, crystallizing the amorphous silicon at a relatively low temperature and then improving the crystallinity by irradiating the film with a laser light. The concentration of the catalyst in the crystallized silicon film can be controlled by controlling the concentration of the catalyst in the solution.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: March 18, 1997
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Hisashi Ohtani, Akiharu Miyanaga, Hongyong Zhang, Naoaki Yamaguchi, Atsunori Suzuki
  • Patent number: 5608251
    Abstract: In a semiconductor integrated circuit, a plurality of thin film transistors (TFTs) are formed on the same substrate having an insulating surface. Since gate electrodes formed in the TFTs are electrically insulated each other, voltages are applied independently to gate electrodes in an electrolytic solution during an anodization, to form an anodic oxide in at least both sides of each gate electrode. A thickness of the anodic oxide is changed in accordance with characteristics of the TFT. A width of high resistance regions formed in an active layer of each TFT is changed by ion doping using the anodic oxide having a desired thickness as a mask.
    Type: Grant
    Filed: April 2, 1996
    Date of Patent: March 4, 1997
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Toshimitsu Konuma, Masaaki Hiroki, Hongyong Zhang, Mutsuo Yamamoto, Yasuhiko Takemura
  • Patent number: 5608232
    Abstract: Method or fabricating semiconductor devices such as thin-film transistors by annealing a substantially amorphous silicon film at a temperature either lower than normal crystallization temperature of amorphous silicon or lower than the glass transition point of the substrate so as to crystallize the silicon film. Islands, stripes, lines, or dots of nickel, iron, cobalt, or platinum, silicide, acetate, or nitrate of nickel, iron, cobalt, or platinum, film containing various salts, particles, or clusters containing at least one of nickel, iron, cobalt, and platinum are used as starting materials for crystallization. These materials are formed on or under the amorphous silicon film.
    Type: Grant
    Filed: June 5, 1995
    Date of Patent: March 4, 1997
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Shunpei Yamazaki, Yasuhiko Takemura, Hongyong Zhang, Toru Takayama, Hideki Uochi
  • Patent number: 5605847
    Abstract: An electro-optical device such as a liquid crystal device comprises a transparent substrate and a plurality of thin film transistors for driving pixel electrodes. In order to prevent an undesirable influence of light incident on the thin film transistors, a light shielding layer is interposed between the thin film transistors and the transparent substrate. Another portion of the light-shielding layer which corresponds to the pixel electrodes, has been changed to transparent by selectively oxidizing or nitriding the layer.
    Type: Grant
    Filed: June 2, 1995
    Date of Patent: February 25, 1997
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventor: Hongyong Zhang
  • Patent number: 5605846
    Abstract: A process for manufacturing a semiconductor device, particularly a thin film transistor, by using a crystalline silicon film having excellent characteristics. The process comprises forming a silicon nitride film and an amorphous silicon film in contact thereto, introducing a catalyst element capable of promoting the crystallization of the amorphous silicon film by heating the amorphous silicon film, thereby crystallizing at least a part of the amorphous silicon film, and accelerating the crystallization by irradiating the silicon film with a laser beam or intense light equivalent thereto.
    Type: Grant
    Filed: February 21, 1995
    Date of Patent: February 25, 1997
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Hisahi Ohtani, Akiharu Miyanaga, Hongyong Zhang, Naoaki Yamaguchi
  • Patent number: 5604360
    Abstract: Nickel is introduced to a predetermined region of a peripheral circuit section, other than a picture element section, on an amorphous silicon film to crystallize from that region. After forming gate electrodes and others, sources, drains and channels are formed by doping impurities, and laser is irradiated to improve the crystallization. After that, electrodes/wires are formed. Thereby an active matrix type liquid crystal display whose thin film transistors (TFT) in the peripheral circuit section are composed of the crystalline silicon film whose crystal is grown in the direction parallel to the flow of carriers and whose TFTs in the picture element section are composed of the amorphous silicon film can be obtained.
    Type: Grant
    Filed: May 24, 1994
    Date of Patent: February 18, 1997
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Hongyong Zhang, Toru Takayama, Yasuhiko Takemura, Akiharu Miyanaga
  • Patent number: 5595944
    Abstract: A process for fabricating a thin film transistor, which comprises crystallizing an amorphous silicon film, forming thereon a gate insulating film and a gate electrode, implanting impurities in a self-aligned manner, adhering a coating containing a catalyst element which accelerates the crystallization of the silicon film, and annealing the resulting structure at a temperature lower than the deformation temperature of the substrate to activate the doped impurities. Otherwise, the catalyst element can be incorporated into the structure by introducing it into the impurity region by means of ion implantation and the like.
    Type: Grant
    Filed: December 21, 1994
    Date of Patent: January 21, 1997
    Assignee: Semiconductor Energy Laboratory Co., Inc.
    Inventors: Hongyong Zhang, Toru Takayama, Yasuhiko Takemura
  • Patent number: 5595923
    Abstract: A substance containing a catalyst element is formed so as to closely contact with an amorphous silicon film, or a catalyst element is introduced into the amorphous silicon film. The amorphous silicon film is annealed at a temperature which is lower than a crystallization temperature of usual amorphous silicon, thereby selectively crystallizing the amorphous silicon film. The crystallized region is used as a crystalline silicon TFT which can be used in a peripheral driver circuit of an active matrix circuit. The region which remains amorphous is used as an amorphous silicon TFT which can be used in a pixel circuit. A relatively small amount of a catalyst element for promoting crystallization is added to an amorphous silicon film, and an annealing process is conducted at a temperature which is lower than the distortion temperature of a substrate, thereby crystallizing the amorphous silicon film.
    Type: Grant
    Filed: June 6, 1995
    Date of Patent: January 21, 1997
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Hongyong Zhang, Hideki Uochi, Toru Takayama, Yasuhiko Takemura, Mutsuo Yamamoto
  • Patent number: 5583369
    Abstract: Thin-film semiconductor devices such as TFTs (thin-film transistors) and methods of fabricating the same. TFTs are formed on an insulating substrate. First, a substantially amorphous semiconductor coating is formed on the substrate. A protective coating transparent to laser radiation is formed on the semiconductor coating. The laminate is irradiated with laser radiation to improve the crystallinity of the semiconductor coating. Then, the protective coating is removed to expose the surface of the semiconductor coating. A coating for forming a gate-insulating film is formed. Subsequently, gate electrodes are formed. Another method relates to fabrication of semiconductor devices such as TFTs on an insulating substrate. After forming a first coating consisting mainly of aluminum nitride, a second coating consisting principally of silicon oxide is formed. Semiconductor devices such as TFTs or semiconductor circuits are built on the second coating serving as a base layer.
    Type: Grant
    Filed: March 12, 1996
    Date of Patent: December 10, 1996
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Shunpei Yamazaki, Hongyong Zhang, Yasuhiko Takemura
  • Patent number: 5580800
    Abstract: A thin film transistor according to this invention has a gate electrode comprising a lower layer of aluminum of a high purity of over 99.5% and an upper layer of aluminum containing over 0.5% silicon. Alternatively, it has a gate electrode made by adding a IIIa group element to a IIIb group element. Residues produced by the etching of the silicon-containing aluminum gate electrode are etched with a mixture solution of hydrofluoric acid, nitric acid and acetic acid. After contact holes have been formed in an interlayer insulating film, laser annealing is carried out, and metal electrodes are formed in the contact holes thereafter.
    Type: Grant
    Filed: March 15, 1994
    Date of Patent: December 3, 1996
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Hongyong Zhang, Yasuhiko Takemura, Hideki Uochi, Itaru Koyama, Minoru Miyazaki, Akane Murakami, Toshimitsu Konuma, Akira Sugawara, Yukiko Uehara
  • Patent number: 5578520
    Abstract: A method for manufacturing a semiconductor device including preparing a multi-chamber system having at least first and second chambers, the first chamber for forming a film and the second chamber for processing an object with a laser light; processing a substrate in one of the first and second chambers; transferring the substrate to the other one of the first and second chambers; and processing the substrate in the other one of the chambers, wherein the first and second chambers can be isolated from one another by using a gate valve.
    Type: Grant
    Filed: July 15, 1994
    Date of Patent: November 26, 1996
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Hongyong Zhang, Naoto Kusumoto
  • Patent number: 5576556
    Abstract: A monolithic circuit comprises a plurality of thin film transistors. Source and drain regions of the TFT are provided with a metal silicide layer having a relatively low resistivity. Thereby, the effective distance between a gate and a source/drain electrode can be reduced.
    Type: Grant
    Filed: August 16, 1994
    Date of Patent: November 19, 1996
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Yasuhiko Takemura, Hongyong Zhang, Toshimitsu Konuma
  • Patent number: 5576225
    Abstract: An improved method of forming insulated gate field effect transistors is described. In accordance with the method, gate electrodes are formed from metal such as aluminum together with wirings electrically connecting the gate electrodes. The gate electrodes are anodic oxidized by dipping them as an anode in an electrolyte to form an oxide of the metal covering them. Since the connecting wirings are covered with a suitable organic film before the anodizing, no aluminum oxide is formed thereon so that it is easy to remove the connecting wiring by usual etching.
    Type: Grant
    Filed: April 28, 1993
    Date of Patent: November 19, 1996
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Hongyong Zhang, Hideki Uochi, Hiroki Adachi, Itaru Koyama, Shunpei Yamazaki
  • Patent number: 5569936
    Abstract: A substance containing a catalyst element is formed so as to closely contact with an amorphous silicon film, or a catalyst element is introduced into the amorphous silicon film. The amorphous silicon film is annealed at a temperature which is lower than a crystallization temperature of usual amorphous silicon, thereby selectively crystallizing the amorphous silicon film. The crystallized region is used as a crystalline silicon TFT which can be used in a peripheral driver circuit of an active matrix circuit. The region which remains amorphous is used as an amorphous silicon TFT which can be used in a pixel circuit. A relatively small amount of a catalyst element for promoting crystallization is added to an amorphous silicon film, and an annealing process is conducted at a temperature which is lower than the distortion temperature of a substrate, thereby crystallizing the amorphous silicon film.
    Type: Grant
    Filed: March 8, 1994
    Date of Patent: October 29, 1996
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Hongyong Zhang, Hideki Uochi, Toru Takayama, Yasuhiko Takemura, Mutsuo Yamamoto
  • Patent number: 5569610
    Abstract: Method of fabricating a semiconductor circuit is initiated with formation of an amorphous silicon film. Then, a second layer containing at least one catalytic element is so formed as to be in intimate contact with the amorphous silicon film, or the catalytic element is introduced into the amorphous silicon film. This amorphous silicon film is selectively irradiated with laser light or other equivalent intense light to crystallize the amorphous silicon film.
    Type: Grant
    Filed: March 8, 1994
    Date of Patent: October 29, 1996
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Hongyong Zhang, Toru Takayama, Yasuhiko Takemura