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:
Jan. 20, 2004
Filed:
Dec. 29, 1999
Fumihiko Sato, Tokyo, JP;
NEC Electronics Corporation, Kanagawa, JP;
Abstract
An object of the invention is to minimize variation in characteristics of a vertical bipolar transistor. An insulating side wall spacer composed of a silicon nitride film and a silicon oxide film is formed on the side surface of an opening formed in a base electrode polysilicon film . The thickness (=W ) of the insulating side wall spacer is made thicker than the maximum thickness (=W ) within a range of variation in thickness of a polycrystalline film grown from the side surface of the base electrode polysilicon film exposed inside the opening (namely, W >W ). The size of an opening for forming an emitter electrode polysilicon film on an intrinsic base is not influenced by the thickness of a polycrystalline film epitaxially growing from the side surface of the polysilicon film for the base electrode, but is defined by the side wall spacer formed on a portion of the side surface of the base electrode polysilicon film. Therefore, emitter area hardly disperses, and electric characteristics become stable.