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:
Apr. 11, 1995
Filed:
Jun. 15, 1993
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 as a dielectric film and a silicon nitride film or a polysilicon film as a protection film for the silicon oxide film are formed on a silicon substrate. After the two films are selectively etched to form contact holes of a bipolar transistor, a polysilicon film as a conductive film is laid on the entire substrate and selectively etched to form electrodes. In a MIS transistor, the protection film of the silicon nitride film serves as a gate insulator film and the protection film of the polysilicon film serves as a gate electrode. Accordingly, contamination to the gate insulator film at formation of contact holes of the bipolar transistor is prevented, and an excellent semiconductor with Bi-MOS structure is manufactured with low cost.