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. 08, 1987
Filed:
Aug. 06, 1986
Tadashi Hirao, Itami, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A method for fabricating bipolar transistors comprises a step of forming a multi-layered film consisting of a polysilicon film (600), a silicon nitride film (202) and a silicon oxide film (104) on an emitter region (7) and on an external base region (54, 56), a step of causing the silicon oxide film (104) to recede inwardly from the polysilicon film (600) and silicon nitride (202) film, a step of patterning the polysilicon film (600) by using the inwardly receded oxide film (104) as a mask while defining the external base region (54, 56), a step of forming an emitter region (7) and an active base region (6) by using the patterned polysilicon as an impurity diffusion source while self-alignedly forming an external base region (54, 56), and a step of self-alignedly forming an insulation film (107, 203) for electrical isolation between base and emitter electrode interconnections (9) on the side wall of the polysilicon film (603) by means of anisotropic etching.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile