Claims
- 1. A ferroelectric device including a layered superlattice material compound comprising A-site metal and a plurality of B-site metals selected from the group consisting of titanium, tantalum and niobium, said compound having a polarizability 2P, of at least about 15 microcoulombs per square centimeter, said compound being in a film having a thickness not greater than about 3500 .ANG..
- 2. A ferroelectric device as in claim 1 wherein said layered superlattice material comprises a solid solution of two or more materials from the group comprising strontium bismuth tantalate, strontium bismuth niobate, and strontium bismuth titanate.
- 3. A layered superlattice material compound having an average grain size of from 200 .ANG. to 2000 .ANG., said layered superlattice material compound having a porosity suitable for use in integrated circuit applications, said layered superlattice material compound having a thickness not greater than about 3500 .ANG..
- 4. A layered superlattice material as in claim 3 wherein said material is ferroelectric.
- 5. A ferroelectric layered superlattice material compound having a polarizability 2Pr greater than 15 microcoulombs per square centimeter, said ferroelectric layered superlattice material compound having a thickness no greater than about 3500 .ANG..
- 6. A ferroelectric device as in claim 2 wherein said layered superlattice material comprises an amount of bismuth, as compared to the amount of other metals, in excess of the proportion of bismuth in the stoichiometric formula for said layered superlattice material.
- 7. A ferroelectric device as in claim 6 wherein said amount of bismuth is between 105% and 140% of the normal stoichiometric amount of bismuth.
- 8. A ferroelectric device as in claim 1 wherein said layered superlattice material comprises a material having the formula:
- SrBi.sub.4-2x+.alpha. {(Ta.sub.y,Nb.sub.1-y).sub.x Ti.sub.2-2x }.sub.2 O.sub.15-6x
- where 0.ltoreq.x.ltoreq.1.0, 0.ltoreq.y.ltoreq.1.0, and 0.ltoreq..alpha..ltoreq.1.6(2-x).
- 9. A ferroelectric device as in claim 8 wherein: 0.7.ltoreq.x.ltoreq.1.0, 0.8.ltoreq.y.ltoreq.1.0, and 0.ltoreq..alpha..ltoreq.1.2(2-x).
- 10. A ferroelectric device as in claim 2 wherein said layered superlattice material has an average grain size of from 200 .ANG. to 2000 .ANG..
Parent Case Info
This application is a divisional from U.S. patent application Ser. No. 08/065,656, filed May 21, 1993, now U.S. Pat. No. 5,434,102 which is a continuation-in-part of U.S. patent application Ser. No. 07/981,133 filed Nov. 24, 1992 U.S. Pat. No. 5,423,285 and Ser. No. 07/965,190 filed Oct. 23, 1992 now abandoned, which in turn are continuations-in-part of U.S. patent application Ser. No. 07/807,439 filed Dec. 13, 1991, now abandoned, which is a continuation-in-part of U.S. patent application Ser. No. 07/660,428 filed Feb. 25, 1991 now abandoned.
US Referenced Citations (3)
Number |
Name |
Date |
Kind |
4793872 |
Meunier et al. |
Dec 1988 |
|
5146299 |
Lampe et al. |
Sep 1992 |
|
5206788 |
Larson et al. |
Apr 1993 |
|
Foreign Referenced Citations (1)
Number |
Date |
Country |
2-232974 |
Sep 1990 |
JPX |
Non-Patent Literature Citations (2)
Entry |
Smolenskii et al., "Ferroelectrics of the Oxygen-Octahedral type with Layered Structure," Soviet Physics-Solid State, vol. 3, No. 3, Sep., 1961, pp. 651-655. |
Subbarao, "A Family of Ferroelectric Bismuth Compounds," J. Phys. Chem. Solids, Pergamon Press, 1962, vol. 23, pp. 665-676. |
Divisions (1)
|
Number |
Date |
Country |
Parent |
65656 |
May 1993 |
|
Continuation in Parts (3)
|
Number |
Date |
Country |
Parent |
981133 |
Nov 1992 |
|
Parent |
807439 |
Dec 1991 |
|
Parent |
660428 |
Feb 1991 |
|