Chemistry of inorganic compounds – Oxygen or compound thereof – Metal containing
Reexamination Certificate
1998-04-30
2001-02-06
Jones, Deborah (Department: 1775)
Chemistry of inorganic compounds
Oxygen or compound thereof
Metal containing
C423S617000, C423S635000, C423S641000
Reexamination Certificate
active
06183715
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the field of low dielectric constant materials for use as substrates, buffer layers, and dielectric layers in construction of microwave and millimeterwave technology with particular emphasis toward substrates for microwave perovskite oxide devices including high critical temperature superconductors, ferroelectrics, magnetoresistors, conductors, semi-conductors, piezoelectrics, paraelectrics, pyroelectrics, etc.
SUMMARY OF THE INVENTION
Until now, the polarizability of Sb
5+
was unknown. By constructing numerous compositions of matter including compositions which contain pentavalent antimonate (Sb
5+
), and by measuring the dielectric constants of these compositions, it has been determined that Sb
5+
has an unordinarily low polarizability which results in the fabrication of low dielectric constant materials as determined using the polarizability rule. These substrates may be suitable as microwave compatible substrates upon determination of the loss tangent by measurement. The basic difficulty associated with lowering the dielectric constant of a material has to do with the atoms that comprise the structure, the polarizability of those atoms, the volume of space tht those atoms occupy (which depends on the crystal structure for crystalline materials or the packing arrangement for amorphous, polymeric as well as other types of materials). The precise relationships for predicting dielectric constants can be found in Shannon et al. [Dielectric polarizabilities of ions in oxides and fluorides], J. Apply. Phys., 73, 348(1993). However, until now, there has been no determination of the low polarizability of Sb
5+
which is a key to manufacturing lower dielectric constants as substrates and dielectric layers for use as structures especially in microwave devices.
Accordingly, it is an object of this invention to provide a low dielectric constant material for use as a substrate and dielectric layers particularly for various microwave devices. It is another object of this invention to provide suitably low dielectric constant microwave compatible substrates that satisfy the requirements for the majority of perovskite oxide single and multilayer microwave devices. Since microwave device requirements are typically more stringent than non-microwave device requirements, such substrates can also be used for most non-microwave devices. Further, it is another object of this invention to provide a suitably low dielectric constant microwave compatible substrate that satisfies the requirements for the majority of all HTSC thin film single and multilayer microwave and non-microwave devices. It is a further objective of this invention to provide a suitably low dielectric constant microwave compatible substrate that satisfies the requirements for the majority of ferroelectric, pyroelectric, piezoelectric, magnetoresistive, paraelectric etc. thin film single and multilayer microwave and non-microwave devices. Some of the specific materials shown here will provide lattice matching and chemical compatibility with many such perovskite oxide films and hence provide the foundation for epitaxial growth of high quality devices which translate into high quality device structures and microwave devices.
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Whitman, G. Rauser and Kemmler-Sack, S., “Uber die Ordnung von Blll und MV in Perowskiten vom Typ A2IIBIIMVO6” Z. aNORG aLLG. cHEM., No. 482, pp. 143-153. (No Month), 1981.
Fesenko, E.G. et al., “Synthesis and Study of A2Sb5 + B'06 and A3Sb25 +B'o9-Type Ternary Oxide Perovskite Structure,” Isv. Akad. Nauk SSSR, Neorg. Matter., 6(4), 800-2 (Russian) pp. 800-802. (No Month), 1970.
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Finnegan Robert D.
Tauber Arthur
Tidrow Steven C.
Wilber William D.
Clohan, Jr. Paul S.
Jones Deborah
Stein Stephen
The United States of America as represented by the Secretary of
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