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US5972096A
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Coating solutions for use in forming bismuth-based ferroelectric thin films
Assignee: Tokyo Ohka Kogyo Co Ltd
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Filing: 1998-01-15
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Granted: 1999-10-26
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Expires: 2018-01-15
Abstract
Abstract The invention discloses a coating solution for use in forming Bi-based ferroelectric thin films containing Bi, metallic element A (at least one selected from the group consisting of Bi. Pb, Ba, Sr, Ca, Na, K and rare earth elements) and metallic element B (at least one selected from the group consisting of Ti, Nb, Ta, W, Mo, Fe, Co and Cr), wherein it contains metal alkoxides of Bi, metallic element A and metallic element B respectively, and contains composite metal alkoxides formed by any two or more of said metal alkoxides; and a ferroelectric thin film, a ferroelectric capacitor and a ferroelectric memory formed by the use of such coating solution, and a method for producing the same.
Inventors
- 👤 Yoshihiro Sawada
- 👤 Akira Hashimoto
- 👤 Tetsuya Osaka
- 👤 Ichiro Koiwa
- 👤 Juro Mita
- 👤 Yoshinori Maeno
- 👤 Yukihisa Okada
- 👤 Hiroyo Kato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 04:37
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/60; H10P14/65; H10P14/6516; H10P14/6544; C; C01; C01G; C01G33/00; C01G33/006; C01G35/00; C01G35/006; C23; C23C; C23C16/00; C23C16/22; C23C16/30; C23C16/40; C23C16/44; C23C16/448; H10D; H10D1/00; H10D1/60; H10D1/68; H10D1/682; C01P; C01P2002/00; C01P2002/70; C01P2002/72; C01P2004/00; C01P2004/80; C01P2006/00; C01P2006/40; H10P14/63; H10P14/6326; H10P14/6342; H10P14/69; H10P14/692; H10P14/6938; H10P14/69398; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24802; Y10T428/24917
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
115 words
A coating solution for use in forming Bi-based ferroelectric thin films containing metal alkoxides of Bi, metallic element A, wherein A is at least one metallic element selected from the group consisting of Bi, Pb, Ba, Sr, Ca, Na, K and rare earth elements, metallic element B, wherein B is at least one metallic element selected from the group consisting of Ti, Nb, Ta, W, Mo, Fe, Co and Cr, and an organometallic compound obtainable by hydrolyzing composite metal alkoxides formed by any two or more of said metal alkoxides by addition of water alone or in combination with a catalyst, followed by stirring at 20 to 50° C. for several hours to several days.
Claim 2
Dependent Claim
115 words
A coating solution for use in forming Bi-based ferroelectric thin films containing metal alkoxides of Bi, metallic element A, wherein A is at least one metallic element selected from the group consisting of Bi, Pb, Ba, Sr, Ca, Na, K and rare earth elements, metallic element B, wherein B is at least one metallic element selected from the group consisting of Ti, Nb, Ta, W, Mo, Fe, Co and Cr, and an organometallic compound obtainable by hydrolyzing composite metal alkoxides formed by any two or more of said metal alkoxides by addition of water alone or in combination with a catalyst, followed by stirring at 20 to 50° C. for several hours to several days.
Claim 3
Dependent Claim
96 words
The coating solution for use in forming Bi-based ferroelectric thin films according to claim 1, wherein said Bi-based ferroelectric thin films are represented by the general formula (I): A.sub.a Bi.sub.x B.sub.b O.sub.y (I) where A is at least one metallic element selected from the group consisting of Bi, Pb, Ba, Sr, Ca, Na, K and rare earth elements; B is at least one metallic element selected from the group consisting of Ti, Nb, Ta, W, Mo, Fe, Co and Cr; and 1≦x≦4, 0.5≦a≦2, 2≦b≦5, and y=[3x+a (valency of metallic element A)+b (valency of metallic element B)]/2.
Claim 4
Dependent Claim
39 words
The coating solution for use in forming Bi-based ferroelectric thin films according to claim 1, wherein said Bi-based ferroelectric thin films are represented by the general formula (II): Sr.sub.a Bi.sub.x (Ta.sub.2-c, Nb.sub.c)O.sub.y (II) where, 1≦x≦4, 0.5≦a≦2, y=(3x+2a+5c)/2, and 0≦c<2.
Claim 5
Dependent Claim
40 words
The coating solution for use in forming Bi-based ferroelectric thin film according to claim 1, wherein said organometallic compound obtainable by hydrolyzing the composite metal alkoxides with water alone or in combination with a catalyst, is reacted with a stabilizer.
Claim 6
Dependent Claim
48 words
The coating solution for use in forming Bi-based ferroelectric thin films according to claim 1, wherein said coating solution contains an organometallic compound obtainable by reacting said metal alkoxides with a stabilizer, followed by hydrolyzing the resultant reaction product with water alone or in combination with a catalyst.
Claim 7
Dependent Claim
25 words
The coating solution for use in forming Bi-based ferroelectric thin films according to claim 5, wherein said organometallic compound is further reacted with the stabilizer.
Claim 8
Dependent Claim
42 words
The coating solution for use in forming Bi-based ferroelectric thin films according to any one of claims 4, 5 and 6, wherein the stabilizer is at least one selected from the group consisting of carboxylic anhydrides, dicarboxylic acid monoesters, β-diketones, and glycols.
Claim 9
Dependent Claim
51 words
A coating solution for use in forming Bi-based ferroelectric thin films according to claim 7, wherein the carboxylic anhydride is at least one of carboxylic anhydrides represented by the general formula (III): R.sup.1 (CO).sub.2 O (III) where R 1 is a divalent saturated or unsaturated hydrocarbon group having 1-6 carbon atoms.
Claim 10
Dependent Claim
68 words
A coating solution for use in forming Bi-based ferroelectric thin films according to claim 7, wherein the dicarboxylic acid monoester is at least one of the dicarboxylic acid monoesters represented by the general formula (IV): R.sup.2 OCOR.sup.3 COOH (IV) where R 2 is a saturated or unsaturated hydrocarbon group having 1-6 carbon atoms; and R 3 is a divalent saturated or unsaturated hydrocarbon group having 1-6 carbon atoms.
Claim 11
Dependent Claim
70 words
The coating solution for use in forming Bi-based ferroelectric thin films according to claim 7, wherein the β-diketone is at least one of the β-diketones represented by the general formula (V): R.sup.4 COCR.sup.5 HCOR.sup.6 (V) where R 4 is a saturated or unsaturated hydrocarbon group having 1-6 carbon atoms; R 5 is H or CH 3 ; and R 6 is an alkyl or alkoxyl group having 1-6 carbon atoms.
Claim 12
Dependent Claim
49 words
A coating solution for use in forming Bi-based ferroelectric thin films according to claim 7, wherein the glycol is at least one of the glycols represented by the general formula (VI): HOR.sup.7 OH (VI) where R 7 is a divalent saturated or unsaturated hydrocarbon group having 1-6 carbon atoms.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2002-10-25 | 2003-04-26 | 2003-10-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-10-25 | 2007-04-26 | 2007-10-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-10-25 | 2011-04-26 | 2011-10-26 | $7700.00 | Window Closed / Lapsed |