The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 14, 1993
Filed:
Jan. 02, 1992
Koji Kimura, Kawasaki, JP;
Shin-ichi Taka, Yokosuka, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
According to this invention, in a method of manufacturing a bipolar transistor, a first oxide film, a nitride film, a first polysilicon film containing boron, and a second oxide film are formed on a substrate. A first opening is formed in the second oxide film and the first polysilicon film. The nitride film and the first oxide film are etched in and near the first opening to form overhung portions between the substrate and the first semiconductor film around the first opening. A second polysilicon film for burying the overhung portions is formed on the entire surface of the resultant structure. Thereafter, boron in the second polysilicon film is thermally diffused in the substrate to form an external base region and a link region. The second polysilicon film is etched to leave the second polysilicon film at only the overhung portions. After an internal base region formed in the substrate. Thereafter, an emitter region formed in the internal base region.