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:
Oct. 09, 1990
Filed:
Feb. 07, 1990
Applicant:
Inventors:
Kyoichiro Asayama, Tachikawa, JP;
Hiroyuki Miyazawa, Kodaira, JP;
Yutaka Kobayashi, Katsuta, JP;
Seigou Yukutake, Hitachi, JP;
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01L / ;
U.S. Cl.
CPC ...
437 31 ; 437 34 ; 437 59 ; 437 48 ; 437 52 ; 357 34 ; 357 43 ; 357 42 ;
Abstract
A method for producing a memory LSI having in its peripheral circuitry an MISFET of LDD structure and a vertical type bipolar transistor is disclosed. More particularly, an impurity for forming a low impurity concentration region of the said MISFET of LDD structure is introduced sideways of an emitter-base junction of the bipolar transistor. By the introduction of the said impurity, an effective impurity concentration near the base surface is reduced and the cut-off frequency of the bipolar transistor is improved.