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. 05, 1993
Filed:
Jan. 28, 1991
Applicant:
Inventors:
Akihisa Uchida, Tokyo, JP;
Yuji Yatsuda, Tokyo, JP;
Katsumi Ogiue, Tokyo, JP;
Kazuo Nakazato, Tokyo, JP;
Takahiro Onai, Tokyo, JP;
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01L / ; H01L / ;
U.S. Cl.
CPC ...
257477 ; 257566 ; 257577 ; 257578 ; 257586 ;
Abstract
A bipolar SRAM which includes a forward bipolar transistor and a reverse bipolar transistor on an identical semiconductor substrate, is disclosed. Concretely, the base region of the reverse bipolar transistor is formed at a deeper position of the substrate than the base region of the forward bipolar transistor, thereby to heighten the cutoff frequency f.sub.T of the reverse bipolar transistor.