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:
Aug. 18, 1992
Filed:
Dec. 19, 1990
Ciaran J Brennan, Allston, MA (US);
The Charles Stark Draper Laboratory, Inc., Cambridge, MA (US);
Abstract
A ferroelectric space charge capacitor memory device includes a pair of spaced first and second electrodes; a ferroelectric dielectric disposed between the electrodes; means for applying a coercive voltage to the dielectric to write the dielectric into one of two polarization states and to establish in each polarization state in the dielectric a space charge region proximate each electrode having a charge opposite to that of the electrode with a neutral region between the space charge regions, the relative sizes of the neutral and space charge regions defining the capacitance of the dielectric, the neutral region having an internal polarization field opposite to that represented by the space charge regions; means for applying to the dielectric a bias voltage less than the coercive voltage at a rate lower than the rate of space charge formation to define a capacitance level representative of one of the polarization states; means for introducing to the dielectric a read signal at a rate faster than the rate of space charge formation, which together with the bias voltage is less than the coercive voltage; and means responsive to the introduction of the read signal to the dielectric for determining the capacitance level representative of one of the polarization states.