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:
Feb. 03, 2009
Filed:
Jul. 06, 2006
Applicants:
Noriyuki Kawashima, Kanagawa, JP;
Kenichi Taira, Kanagawa, JP;
Inventors:
Noriyuki Kawashima, Kanagawa, JP;
Kenichi Taira, Kanagawa, JP;
Assignee:
Sony Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01L 21/336 (2006.01); H01L 21/3205 (2006.01); H01L 21/4763 (2006.01);
U.S. Cl.
CPC ...
Abstract
There is provided a nonvolatile semiconductor storage device less subject to variances of electric characteristics among memory cells. A floating gate electrode provided on a substrate is made of two or more materials different in carrier trapping efficiency so as to accumulate carriers and thereby store data in the floating gate electrode. Thus a region without so large changes of the threshold voltage is produced, and the portion with a small change is used as the margin for circuit operations, thereby to eliminate variances among cells and realize high-speed operations.