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.

Date of Patent:
Aug. 21, 2012

Filed:

Mar. 05, 2010
Applicants:

Tadashi Miyakawa, Kanagawa-ken, JP;

Daisaburo Takashima, Kanagawa-ken, JP;

Inventors:

Tadashi Miyakawa, Kanagawa-ken, JP;

Daisaburo Takashima, Kanagawa-ken, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11C 11/12 (2006.01);
U.S. Cl.
CPC ...
Abstract

Semiconductor memory contains memory cells having ferroelectric capacitors and cell transistors, bit lines connected to memory cells, word lines connected to gate electrodes of cell transistors, plate lines connected to one of two electrodes of ferroelectric capacitors, sense amplifiers connected between each pair of bit lines. Further, a test pad is provided in order to apply an external voltage to each of bit lines, test transistors are provided corresponding to bit lines respectively, each of test transistors is connected between the test pad and each of bit lines, a fatigue test bias circuit is connected to a first node located between the test pad and test transistors. Test transistors are shared in a first test to apply a first voltage to ferroelectric capacitors from an outside via the test pad and a second test to apply a second voltage to ferroelectric capacitors from the fatigue test bias circuit.


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