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. 11, 2003
Filed:
Jan. 08, 2002
Yoshihiro Tada, Kyoto, JP;
Rohm Co., Ltd., Kyoto, JP;
Abstract
A ferroelectric storage device having 2Tr-2C cell structure or 1Tr-1C cell structure, which can be assessed by a screening test. In the test, a regulated reference voltage is supplied from an external reference voltage input terminal to one end of a sense amplifier. The bit line voltage of the memory cell is input to the other terminal of the sense amplifier. Characteristics of the ferroelectric capacitor are determined quantitatively by measuring the bit line voltages by changing the reference voltage. Deviations in characteristics and degrees of defect/degradation of ferroelectric capacitors can be assessed by such measurement to improve the reliability of the ferroelectric storage device.