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. 17, 1998
Filed:
Aug. 20, 1997
Takehiro Hirai, Osaka, JP;
Masahiro Nakatani, Ishikawa, JP;
Mitsuo Tanaka, Osaka, JP;
Akihiro Kanda, Osaka, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A silicon oxide film and a polysilicon film are formed on a silicon substrate and are selectively etched to form a contact hole in a region where an emitter is to be formed. A polysilicon film is laid on the substrate and two polysilicon films are patterned to form an emitter electrode and a gate electrode made of the two polysilicon films which are doped with arsenic. The arsenic is diffused from the polysilicon films of the emitter electrode into the silicon substrate to form an N.sup.+ emitter layer which has a high concentration and is shallow. Consequently, the contamination of a gate insulator film can be prevented from occurring and a bipolar transistor having high performance, for example, a high current amplification factor or the like can be formed.