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:
Nov. 07, 1989
Filed:
Jan. 25, 1988
Shigeru Komatsu, Kitakyushu, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
The method of manufacturing a semiconductor device according to the present invention comprises the step of forming an opening in use for forming an emitter region. This step uses the independent etching characteristics of N and P type polysilicons to simplify the opening forming process, which is very complicated in the conventional method. To be more specific, the impurity doped in the first polysilicon layer at a high concentration is diffused into the second polysilicon layer adjacent to the first polysilicon layer. When the impurity doped in the first polysilicon layer is diffused into the second polysilicon layer, the diffused impurity dominantly determines the conductivity type of that portion of the second polysilicon layer, into which the impurity is diffused. Therefore, one of the first polysilicon layer and the second polysilicon layer portion is etched by a solution, independently of the other. Since they are etched independently, a desired gap can be formed between the end portion of the first plysilicon layer and the emitter electrode.