US5463244A
Expired / Lapsed
US
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Antifuse programmable element using ferroelectric material
Assignee: Symetrix Corp
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Filing: 1994-05-26
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Granted: 1995-10-31
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Expires: 2014-05-26
Abstract
Abstract An electrically programmable antifuse element using ferroelectric materials for the insulative dielectric layer, methods for producing same, and an integrated circuit applying a plurality of ferroelectric antifuse elements in a two dimensional matrix of rows and columns for use as a programmable logic device (PLD) or as a programmable read-only memory (PROM). A ferroelectric material is formed between two conductive electrodes to create a ferroelectric antifuse element. In an alternative embodiment, a plurality of chemically distinct materials is layered to form the dielectric layer. The combined application of an AC electric field and a DC electric field breaks down the ferroelectric material to form a low-resistance conductive filament. The synergy of the two electric fields permits programming antifuse elements of the present invention by applying DC electric fields as low as 2 volts amplitude. In the preferred embodiment, as compared to prior designs, antifuse devices of the present invention display higher resistivity in the unprogrammed state due to the high dielectric constant of ferroelectric materials and lower resistivity in the programmed state because the ferroelectric material breaks down into metal oxide conductive filaments. The resistivity of the conductive filament may be reduced further by the blending of materials through substitution rather than doping processes.
Inventors
- 👤 Carlos A. P. De Araujo
- 👤 Larry D. McMillan
- 👤 Joseph D. Cuchiaro
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 01:37
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/40; H10W20/49; H10W20/491
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
50 words
An electrically programmable antifuse device comprising: first and second electrodes; a dielectric layer electrically insulating said first electrode from said second electrode, said dielectric layer comprising a layered superlattice material; and fusing means for controllably altering said dielectric layer to form an electrical conductor connecting said first and second electrodes.
Claim 2
Dependent Claim
50 words
An electrically programmable antifuse device comprising: first and second electrodes; a dielectric layer electrically insulating said first electrode from said second electrode, said dielectric layer comprising a layered superlattice material; and fusing means for controllably altering said dielectric layer to form an electrical conductor connecting said first and second electrodes.
Claim 3
Dependent Claim
22 words
The programmable antifuse device of claim 1 wherein said dielectric layer comprises strontium bismuth titanate (SrBi 2 Ta 2 O 9 ).
Claim 4
Dependent Claim
20 words
The programmable antifuse device of claim 1 wherein said dielectric layer comprises a plurality of layers of physically distinct materials.
Claim 5
Dependent Claim
39 words
The programmable antifuse device of claim 3 wherein said plurality of layers of physically distinct materials comprises a first layer of strontium bismuth titanate (SrBi 2 Ta 2 O 9 ) and a second layer of zinc oxide (ZnO).
Claim 6
Dependent Claim
46 words
The programmable antifuse device of claim 3 wherein said plurality of layers of physically distinct materials comprises a first layer of strontium bismuth titanate (SrBi 2 Ta 2 O 9 ) and a second layer of barium bismuth titanate (Ba x Bi y TiO 3 ).
Claim 7
Dependent Claim
15 words
The programmable antifuse device of claim 1 wherein said first electrode includes a barrier layer.
Claim 8
Dependent Claim
15 words
The programmable antifuse device of claim 1 wherein said second electrode includes a barrier layer.
Claim 9
Dependent Claim
49 words
The programmable antifuse device of claim 1 wherein said fusing means comprises: means for controllably applying an AC electric field of predetermined AC amplitude across said first and second electrodes; and means for controllably applying a DC electric field of predetermined DC amplitude across said first and second electrodes.
Claim 10
Dependent Claim
74 words
An electrically programmable antifuse device comprising: first and second electrodes; a dielectric layer electrically insulating said first and second electrodes, said dielectric layer comprising a plurality of physically distinct materials selected to form a conductive material when fused, wherein at least one of said plurality of physically distinct materials is a layered superlattice material; and fusing means for controllably altering said dielectric layer to form an electrical conductor connecting said first and second electrodes.
Claim 11
Dependent Claim
74 words
An electrically programmable antifuse device comprising: first and second electrodes; a dielectric layer electrically insulating said first and second electrodes, said dielectric layer comprising a plurality of physically distinct materials selected to form a conductive material when fused, wherein at least one of said plurality of physically distinct materials is a layered superlattice material; and fusing means for controllably altering said dielectric layer to form an electrical conductor connecting said first and second electrodes.
Claim 12
Dependent Claim
37 words
The programmable antifuse device of claim 9 wherein said plurality of physically distinct materials comprises a first layer of strontium bismuth titanate (SrBi 2 Ta 2 O 9 ) and a second layer of zinc oxide (ZnO).
Claim 13
Dependent Claim
44 words
The programmable antifuse device of claim 9 wherein said plurality of physically distinct materials comprises a first layer of strontium bismuth titanate (SrBi 2 Ta 2 O 9 ) and a second layer of barium bismuth titanate (Ba x Bi y TiO 3 ).
Claim 14
Dependent Claim
15 words
The programmable antifuse device of claim 9 wherein said first electrode includes a barrier layer.
Claim 15
Dependent Claim
15 words
The programmable antifuse device of claim 9 wherein said second electrode includes a barrier layer.
Claim 16
Dependent Claim
50 words
The programmable antifuse device of claim 9 wherein said fusing means further comprises: means for controllably applying an AC electric field of predetermined AC amplitude across said first and second electrodes; and means for controllably applying a DC electric field of predetermined DC amplitude across said first and second electrodes.
Claim 17
Dependent Claim
122 words
A programmable array integrated circuit comprising: a substrate material; a plurality of row electrode means formed in substantially parallel rows on said substrate material; a plurality of column electrode means formed in substantially parallel columns substantially perpendicular to said plurality of row electrode means, each of said plurality of column electrodes intersecting the plane of each of said plurality of row electrodes; dielectric means for electrically insulating each of said intersecting row and column electrode means, said dielectric means comprising a layered superlattice material; and fusing means for controllably altering said dielectric means at any one of said intersections of said row and column electrode means to form an electrical conductor connecting said one of said intersecting row and column electrode means.
Claim 18
Dependent Claim
122 words
A programmable array integrated circuit comprising: a substrate material; a plurality of row electrode means formed in substantially parallel rows on said substrate material; a plurality of column electrode means formed in substantially parallel columns substantially perpendicular to said plurality of row electrode means, each of said plurality of column electrodes intersecting the plane of each of said plurality of row electrodes; dielectric means for electrically insulating each of said intersecting row and column electrode means, said dielectric means comprising a layered superlattice material; and fusing means for controllably altering said dielectric means at any one of said intersections of said row and column electrode means to form an electrical conductor connecting said one of said intersecting row and column electrode means.
Claim 19
Dependent Claim
23 words
The programmable array integrated circuit of claim 15 wherein said dielectric means comprises strontium bismuth titanate (SrBi 2 Ta 2 O 9 ).
Claim 20
Dependent Claim
52 words
The programmable array integrated circuit of claim 15 wherein said dielectric means comprises a plurality of layers of physically distinct materials, and wherein a low impedance electrically conductive material is formed to electrically connect said intersecting row and column electrode means by operation of said fusing means on said plurality of materials.
Claim 21
Dependent Claim
40 words
The programmable array integrated circuit of claim 17 wherein said plurality of layers of physically distinct materials comprises a first layer of strontium bismuth titanate (SrBi 2 Ta 2 O 9 ) and a second layer of zinc oxide (ZnO).
Claim 22
Dependent Claim
47 words
The programmable array integrated circuit of claim 17 wherein said plurality of layers of physically distinct materials comprises a first layer of strontium bismuth titanate (SrBi 2 Ta 2 O 9 ) and a second layer of barium bismuth titanate (Ba x Bi y TiO 3 ).
Claim 23
Dependent Claim
17 words
The programmable array integrated circuit of claim 15 wherein said row electrode means includes a barrier layer.
Claim 24
Dependent Claim
17 words
The programmable array integrated circuit of claim 15 wherein said column electrode means includes a barrier layer.
Claim 25
Dependent Claim
61 words
The programmable array integrated circuit of claim 15 wherein said fusing means further comprises: means for controllably applying an AC electric field of predetermined AC amplitude across said one of said intersecting row and column electrode means; and means for controllably applying a DC electric field of predetermined DC amplitude across said one of said intersecting row and column electrode means.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-10-30 | 1999-05-01 | 1999-10-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-10-30 | 2003-05-01 | 2003-10-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-10-30 | 2007-05-01 | 2007-10-31 | $7700.00 | Window Closed / Lapsed |