US6104049A
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US
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Ferroelectric memory with ferroelectric thin film having thickness of 90 nanometers or less, and method of making same
Assignee: Panasonic Holdings Corp
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Filing: 1999-01-11
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Granted: 2000-08-15
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Expires: 2019-01-11
Abstract
Abstract A coating of liquid precursor containing a metal is applied to a first electrode, baked on a hot plate in oxygen ambient at a temperature not exceeding 300° C. for five minutes, then RTP annealed at 675° C. for 30 seconds. The coating is then annealed in oxygen or nitrogen ambient at 700° C. for one hour to form a thin film of layered superlattice material with a thickness not exceeding 90 nm. A second electrode is applied to form a capacitor, and a post-anneal is performed in oxygen or nitrogen ambient at a temperature not exceeding 700° C. If the material is strontium bismuth tantalate, the precursor contains u mole-equivalents of strontium, v mole-equivalents of bismuth, and w mole-equivalents of tantalum, where 0.8≦u≦1.0, 2.0≦v≦2.3, and 1.9≦w≦2.1.
Inventors
- 👤 Narayan Solayappan
- 👤 Vikram Joshi
- 👤 Carlos A. Paz de Araujo
- 👤 Larry D. McMillan
- 👤 Shinichiro Hayashi
- 👤 Tatsuo Otsuki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 04:08
CPC Classifications
H; H10; H10D; H10D84/00; H10D84/80; H10B; H10B53/00; H10B53/30; H10D1/00; H10D1/60; H10D1/68; H10D1/682; H10D1/692; H10W; H10W20/00; H10W20/01
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
42 words
A ferroelectric integrated circuit memory cell comprising: a ferroelectric memory element including a polycrystalline ferroelectric thin film and an electrode for applying an electric field to said ferroelectric thin film, said ferroelectric thin film having a thickness of 90 nanometers or less.
Claim 2
Dependent Claim
42 words
A ferroelectric integrated circuit memory cell comprising: a ferroelectric memory element including a polycrystalline ferroelectric thin film and an electrode for applying an electric field to said ferroelectric thin film, said ferroelectric thin film having a thickness of 90 nanometers or less.
Claim 3
Dependent Claim
16 words
A ferroelectric memory cell as in claim 1, wherein said thickness is 50 nanometers or less.
Claim 4
Dependent Claim
22 words
A ferroelectric memory cell as in claim 1, wherein said ferroelectric thin film has a polarizability greater than 7 μC/cm 2 .
Claim 5
Dependent Claim
18 words
A ferroelectric memory cell as in claim 1, wherein said ferroelectric thin film comprises a layered superlattice material.
Claim 6
Dependent Claim
17 words
A ferroelectric memory as in claim 4, wherein said layered superlattice material comprises strontium, bismuth and tantalum.
Claim 7
Dependent Claim
31 words
A ferroelectric memory as in claim 4, wherein said layered superlattice material includes u mole-equivalents of strontium, v mole-equivalents of bismuth, and w mole-equivalents of tantalum, and 0.8≦u≦1.0, 2.0≦v≦2.3, and 1.9≦w≦2.1.
Claim 8
Dependent Claim
18 words
A ferroelectric memory as in claim 3, wherein said layered superlattice material comprises strontium, bismuth, tantalum and niobium.
Claim 9
Dependent Claim
37 words
A ferroelectric memory as in claim 7, wherein said layered superlattice material includes u mole-equivalents of strontium, v mole-equivalents of bismuth, w mole-equivalents of tantalum, and x equivalents of niobium, and 0.8≦u≦1.0, 2.0≦v≦2.3, 1.9≦w≦2.1, 1.9≦x≦2.1 and 1.9≦(w+x)≦2.1.
Claim 10
Dependent Claim
46 words
A ferroelectric integrated circuit memory cell comprising: a ferroelectric memory element including a ferroelectric thin film and an electrode for applying an electric field to said ferroelectric thin film, said ferroelectric thin film comprising a layered superlattice material having a thickness of 90 nanometers or less.
Claim 11
Dependent Claim
46 words
A ferroelectric integrated circuit memory cell comprising: a ferroelectric memory element including a ferroelectric thin film and an electrode for applying an electric field to said ferroelectric thin film, said ferroelectric thin film comprising a layered superlattice material having a thickness of 90 nanometers or less.
Claim 12
Dependent Claim
16 words
A ferroelectric memory cell as in claim 9, wherein said thickness is 50 nanometers or less.
Claim 13
Dependent Claim
22 words
A ferroelectric memory cell as in claim 9, wherein said ferroelectric thin film has a polarizability greater than 7 μC/cm 2 .
References Cited (Backward Citations)
US5046043A
Cited
US5198269A
Cited
EP0489519A2
Cited
US5434102A
Cited
US5519234A
Cited
US5382817A
Cited
US5442585A
Cited
US5821005A
Cited
US5757061A
Cited
US5686745A
Cited
US5833745A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-08-15 | 2004-02-14 | 2004-08-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-08-15 | 2008-02-14 | 2008-08-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-08-15 | 2012-02-14 | 2012-08-15 | $7700.00 | Window Closed / Lapsed |