EP0338158A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Ferroelectric retention method
Assignee: Ramtron International Corp
•
Filing: 1988-09-21
•
Granted: —
•
Expires: 2008-09-21
Abstract
Abstract Polarization retention of a ferroelectric material in a memory cell is improved by open circuiting the write pulse. The depolarizing field is reduced by allowing charge to dissipate through the ferroelectric material, causing a polarizing field.
Inventors
- 👤 Sheffield S. Eaton, Jr.
- 👤 Douglas Butler
- 👤 Michael Parris
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 00:25
CPC Classifications
G; G11; G11C; G11C11/00; G11C11/21; G11C11/22
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
44 words
A method of operating a ferroelectric capacitor to improve data retention therein comprising the steps of: generating a write pulse; coupling said write pulse to an electrode of said capacitor; and open circuiting said electrode prior to changing the potential of said write pulse.
Claim 2
Independent Claim
38 words
A method of improving data retention in a ferroelectric material comprising the steps of: applying a write voltage across the ferroelectric material; and allowing at least a portion of the write voltage to decay through the ferroelectric material.
Claim 3
Dependent Claim
15 words
The method of claim 2 wherein said allowing step comprises open circuiting said write pulse.
Claim 4
Dependent Claim
53 words
The method of claim 2 wherein said applying step comprises coupling said write voltage to one electrode of a capacitor, said ferroelectric material being located in said capacitor, said allowing step comprising controlling said coupling to open circuit said electrode to leave at least a portion of said write voltage on said electrode.
Claim 5
Dependent Claim
37 words
The method of claim 4 including applying said write pulse to said capacitor electrode; then dropping the voltage of said write pulse; then open circuiting said electrode before the voltage of said write pulse reaches zero volts.
Claim 6
Independent Claim
50 words
A method of improving data retention in a ferroelectric capacitor having two electrodes comprising the steps of: impressing a write voltage across said electrodes; then maintaining a polarizing voltage across said electrodes which decays in a time similar to the time allowed by the resistance of the ferroelectric material itself.
Claim 7
Dependent Claim
15 words
The method of claim 6 wherein said maintaining step includes using a substrate bias voltage.
Claim 8
Dependent Claim
18 words
The method of claim 6 wherein said maintaining step comprises open circuiting at least one of said electrodes.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.