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:
Sep. 11, 2001
Filed:
May. 26, 2000
Tohru Takeshima, Kanagawa, JP;
Kouichi Noro, Kanagawa, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
A semiconductor memory device has a first ferroelectric memory cell in which data is written after the device is mounted on a board, and a second ferroelectric memory cell whose capacitance is larger than that of the first ferroelectric memory cell. This second ferroelectric memory cell is utilized as a memory cell in which cipher or the like are written in the fabrication process. The second ferroelectric memory cell is formed with a combination of a plurality of the first ferroelectric memory cells. In order to realize the second ferroelectric memory cell, word lines or plate lines corresponding to a plurality memory-cell rows may be short-circuited. Alternatively, bit lines corresponding to a plurality memory-cell columns may be short-circuited.