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. 30, 1999
Filed:
May. 07, 1997
Applicant:
Inventors:
Natsuo Ajika, Hyogo, JP;
Akinori Matsuo, Tokyo, JP;
Assignees:
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Hitachi, Ltd., Tokyo, JP;
Hitachi Ulsi Engineering Corp., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01L / ;
U.S. Cl.
CPC ...
257315 ; 257316 ; 257320 ; 257323 ; 365185 ;
Abstract
A nonvolatile semiconductor memory device has a plurality of p well regions in a memory cell array region. P well region is independently provided for each erase block. Each p well region is connected to a common well/source line driver, respectively. Well/source line driver is connected to a well/source power supply and a well/block decoder. Therefore, a nonvolatile semiconductor memory device which can inhibit a well disturbance in erase operation can be provided.