Stock material or miscellaneous articles – Structurally defined web or sheet – Discontinuous or differential coating – impregnation or bond
Patent
1995-06-07
1998-02-24
Evans, Elizabeth
Stock material or miscellaneous articles
Structurally defined web or sheet
Discontinuous or differential coating, impregnation or bond
428688, 428689, 428701, 428702, 501138, 501135, 338 22R, 2503383, 252 629R, B32B 300
Patent
active
057210438
ABSTRACT:
The invention described is an improved dielectric material formed as a film on the surface of a substrate by adding lead to an original perovskite material having an original critical grain size to form a lead enhanced perovskite material, then forming a layer of the lead enhanced perovskite material having an average grain size less than the original critical grain size whereby the dielectric constant of the layer is substantially greater than the dielectric constant of the original perovskite material with an average grain size similar to the average grain size of the layer. The critical grain size, as used herein, means the largest grain size such that the dielectric constant starts to rapidly decrease with decreasing grain sizes. Preferably, the lead enhanced perovskite material is further doped with one or more acceptor dopants whereby the resistivity is substantially increased and/or the loss tangent is substantially decreased. Preferably, the original perovskite material has a chemical composition ABO.sub.3, where A is one or more monovalent, divalent or trivalent elements, and B is one or more pentavalent, tetravalent, trivalent or divalent elements.
REFERENCES:
patent: 4101454 (1978-07-01), Kulwicki et al.
patent: 4244830 (1981-01-01), Hennings
patent: 4475091 (1984-10-01), Itakura
patent: 4643984 (1987-02-01), Abe
patent: 5112433 (1992-05-01), Dawson
patent: 5504330 (1996-04-01), Summerfelt
A Modified Barium, titanate for Capacitors, U. Syamaprasad, et al., J. Am.
S. D. Bernstein, Y. Kisler, J. M. Wahl, S. E. Bernacki and S. R. Collins, "Effects of Stoichiometry on PZT Thin Film Capacitor Properties," Mat.
S. Hsu and I. H. Kalish, "Ferrelectrics for Silicon VLSI," Proc. 3rd Inter. Symp. Integrated Ferroelectrics, 475-491 (1991) 1976, pp. 572-575.
B. M. Kulwicki and A. Amin, "Pyroelectric Imaging," To be presented at the 1992 Int'l Symposium on Applications of Ferroelectrics.
Y. Enomoto and A. Yamaji, "Preparation of Uniformly Small-Grained BaTiO.sub.3, " Ceramic Bulletin, vol. 60, No. 5, 1981, pp. 566-570.
T. Murakami and A. Yamaji, "Dy-Doped BaTiO.sub.3 Ceramics for High Voltage Capacitor Use," Ceramic Bulletin, vol. 55, No. 6, 1976, pp. 572-575.
F. Jona and G. Shirane, "Ferroelectric Crystals,"Chapter 5, The Macmillan Company, New York, 1962.
F. A. Kroger, "The Chemistry of Imperfect Crystals,"North-Holland Publishing Coompany--Amsterdam, 1964, pp. 198-201.
R. W. G. Wyckoff, "Crystal Structures,"Interscience Publishers, vol. 2, 1964, pp. 359-421.
S. Yamamichi, T. Sakuma, K. Takemura and Y. Miyasaka, "SrTiO.sub.3 Thin Film Preparation by Ion Beam Sputtering and Its Dielectric Properties," Japn. Journal Applied Physics, vol. 30 (1991), pp. 2193-2196.
Y. Miyasaka and S. Matsubara, "Dielectric Properties of Sputter-Deposited BaTiO.sub.3 -SrTiO.sub.3 Thin Films," IEEE 7th Int. Symp. on Appl. of Ferroelectrics, (1991) pp. 121-124.
K. Koyama, T. Sakuma, S. Yamamichi, H. Watanabe, H. Aoki, S. Ohya, Y. Miyasaka and T. Kikkawa, "A Stacked Capacitor with (Ba.sub.x Sr.sub.1-x)TiO.sub.3 for 256M DRAM," IEDM-91, 823-826 (1991).
P. C. Osbond, N. I. Payne, N. M. Shorrocks, R. W. Whatmore and F. W. Ainer, "Dielectric and Microstructure Properties of Barium Strontium Titanate Ceramics Prepared from Citrate Precursors," IEEE, CH2358, pp. 348-351 (1986).
Eun-Dong Kim, Yoo-Eup Hyung, and Mun-Soo Yun, "PbZrO.sub.3 -Doped (Ba,Sr)TiO.sub.3 -Based Dielectrics for High Voltage Capacitor Applications," Ceramic Bulletin, vol. 70, No. 11, 1991, pp. 1783-1787.
G. R. Love "Energy Storage in Ceramic Dielectrics," J. Am. Ceram. Soc. 73 (2) 323-328.
W. B. Pennebaker "RF Sputtered Strontium Titanate Films," IBM J. Res Develop., Nov. 1969, pp. 687-695.
G. Arlt, D. Hennings, G. de With, "Dielectric Properties of Fine-Grained Barium Titanate Ceramics," J. Appl. Phys., vol. 58, No. 4, 15 Aug. 1985, pp. 1619-1624.
K. Kinoshita and Akihiko Yamaji, "Grain-Size Effects on Dielectric Properties in Barium Titanate Ceramics," J. Appl. Phys., vol. 47, No. 1, Jan. 1976, pp. 371-373.
A. Yamaji, Y. Enomoto, K. Kinoshita, and T. Murakami, "Preparation, Characterization, and Properties of Dy-Doped Small-Grained BaTiO.sub.3 Ceramics," J. Am. Ceramic Society, vol. 60, No. 3-4, Mar.-Apr. 1977, pp. 97-101.
M. Grant Norton, Kathryn P. B. Cracknell and C. Barry Carter, "Pulsed-Lasar Deposition of Barium Titanate Thin Films," J. Am. Ceram. Soc. 75 (7) 1999-2002 (1992).
U. Syamaprasad, R. K. Galgali and B. C. Mohanty, "A Modified Barium Titanate for Capacitors," J. Am. Ceram. Soc. 70 (7) C-147 to C-148 (1987).
C. V. R. Vasant Kumar, R. Pascual and M. Sayer, "Crystallization of Sputtered Lead Zirconate Titanate Films by Rapid Thermal Processing," J. Appl. Phys. 71 (2), 15 Jan. 1992.
Beratan Howard R.
Kulwicki Bernard M.
Summerfelt Scott R.
Evans Elizabeth
Harris James E.
Kesterson James C.
Stoltz Richard A.
Texas Instruments Incorporated
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