Patents by Inventor Hognyong Zhang

Hognyong 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).

  • Method of removing a catalyst substance from the channel region of a TFT after crystallization
    Patent number: 5580792
    Abstract: Method of fabricating a semiconductor device, such as a thin-film transistor, having improved characteristics and improved reliability. The method is initiated with formation of a thin amorphous silicon film on a substrate. A metallization layer containing at least one of nickel, iron, cobalt, and platinum is selectively formed on or under the amorphous silicon film so as to be in intimate contact with the silicon film, or these metal elements are added to the amorphous silicon film. The amorphous silicon film is thermally annealed to crystallize it. The surface of the obtained crystalline silicon film is etched to a depth of 20 to 200 .ANG., thus producing a clean surface. An insulating film is formed on the clean surface by CVD or physical vapor deposition. Gate electrodes are formed on the insulating film.
    Type: Grant
    Filed: February 13, 1995
    Date of Patent: December 3, 1996
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Hognyong Zhang, Hideki Uochi, Toru Takayama, Yasuhiko Takemura
  • Method of fabricating a semiconductor device
    Patent number: 5426064
    Abstract: Method of fabricating a semiconductor device, such as a thin-film transistor, having improved characteristics and improved reliability. The method is initiated with formation of a thin amorphous silicon film on a substrate. A metallization layer containing at least one of nickel, iron, cobalt, and platinum is selectively formed on or under the amorphous silicon film so as to be in intimate contact with the silicon film, or these metal elements are added to the amorphous silicon film. The amorphous silicon film is thermally annealed to crystallize it. The surface of the obtained crystalline silicon film is etched to a depth of 20 to 200.ANG., thus producing a clean surface. An insulating film is formed on the clean surface by CVD or physical vapor deposition. Gate electrodes are formed on the insulating film.
    Type: Grant
    Filed: March 8, 1994
    Date of Patent: June 20, 1995
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Hognyong Zhang, Hideki Uochi, Toru Takayama, Yasuhiko Takemura