Tunable dielectric compositions including low loss glass

• US 6,905,989 B2
• Filed: 05/31/2002
• Issued: 06/14/2005
• Est. Priority Date: 06/01/2001
• Status: Expired due to Term

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Paratek Microwave Incorporated (Blackberry Limited)
• Inventors: Winn, Steven Wesley, Ellis, Marion E., Chiu, Luna H.
• Primary Examiner(s): Sample, David
• Assistant Examiner(s): Bolden, Elizabeth A.
• Application Number:
  US10/161,483
• Publication Number:
  US 20030073565A1
• Time in Patent Office: 1,110 Days
• Field of Search: 501/32, 501 65- 67, 501134-139
• US Class Current: 501/32
• CPC Class Codes: B32B 18/00 Layered products essentially comprising ceramics, e.g. refractory products
• CPC Class Codes: B32B 2311/04 Gold
• CPC Class Codes: C03C 14/00 Glass compositions containing a non-glass component, e.g. compositions containing fibres, filaments, whiskers, platelets, or the like, dispersed in a glass matrix devitrified glass ceramics C03C10/00
• CPC Class Codes: C04B 2235/3206 Magnesium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3208 Calcium oxide or oxide-forming salts thereof, e.g. lime
• CPC Class Codes: C04B 2235/3213 Strontium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3215 Barium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3222 Aluminates other than alumino-silicates, e.g. spinel (MgAl2O4)
• CPC Class Codes: C04B 2235/3236 Alkaline earth titanates
• CPC Class Codes: C04B 2235/3436 Alkaline earth metal silicates, e.g. barium silicate
• CPC Class Codes: C04B 2235/3445 Magnesium silicates, e.g. forsterite
• CPC Class Codes: C04B 2235/3454 Calcium silicates, e.g. wollastonite
• CPC Class Codes: C04B 2235/36 Glass starting materials for making ceramics, e.g. silica glass
• CPC Class Codes: C04B 2235/365 Borosilicate glass
• CPC Class Codes: C04B 2237/34 Oxidic
• CPC Class Codes: C04B 2237/343 Alumina or aluminates
• CPC Class Codes: C04B 2237/346 Titania or titanates
• CPC Class Codes: C04B 2237/348 Zirconia, hafnia, zirconates or hafnates
• CPC Class Codes: C04B 2237/40 Metallic
• CPC Class Codes: C04B 2237/408 Noble metals, e.g. palladium, platina or silver
• CPC Class Codes: C04B 35/04 : based on magnesium oxide
• CPC Class Codes: C04B 35/16 : based on silicates other than clay zircon C04B35/48
• CPC Class Codes: C04B 35/20 : rich in magnesium oxide , e.g. forsterite C04B35/195 takes precedence
• CPC Class Codes: C04B 35/22 : rich in calcium oxide , e.g. wollastonite C04B35/195 takes precedence
• CPC Class Codes: C04B 35/443 : Magnesium aluminate spinel
• CPC Class Codes: C04B 35/462 : based on titanates
• CPC Class Codes: C04B 35/465 : based on alkaline earth metal titanates
• CPC Class Codes: C04B 35/4682 : based on BaTiO3 perovskite phase
• CPC Class Codes: C04B 35/495 : based on vanadium, niobium, tantalum, molybdenum or tungsten oxides or solid solutions thereof with other oxides, e.g. vanadates, niobates, tantalates, molybdates or tungstates
• CPC Class Codes: H01G 4/1227 : based on alkaline earth titanates
• CPC Class Codes: H01G 7/06 : having a dielectric selected for the variation of its permittivity with applied voltage, i.e. ferroelectric capacitors electrets H01G7/02

Abstract

Tunable dielectric materials including an electronically tunable dielectric ceramic and a low loss glass additive are disclosed. The tunable dielectric may comprise a ferroelectric perskovite material such as barium strontium titanate. The glass additive may comprise boron, barium, calcium, lithium, manganese, silicon, zinc and/or aluminum-containing glasses having dielectric losses of less than 0.003 at 2 GHz. The materials may further include other additives such as non-tunable metal oxides and silicates. The low loss glass additive enables the materials to be sintered at relatively low temperatures while providing improved properties such as low microwave losses and high breakdown strengths.

Claims

1. A tunable dielectric material comprising:

a tunable dielectric ceramic; and

a low loss glass additive.

2. The tunable dielectric material of claim 1, wherein the low loss glass additive comprises boron-containing glass, calcium-containing glass and/or aluminum-containing glass.

3. The tunable dielectric material of claim 1, wherein the low loss glass additive comprises B and at least one other element selected from Si, Al, Li, Na, K, Ba, Zn, Mn and Ca.

4. The tunable dielectric material of claim 1, wherein the low loss glass additive comprises Ca and at least one other element selected from B, Al, Si, Ba, Zn, Li, Mn and Sr.

5. The tunable dielectric material of claim 1, wherein the low loss glass additive comprises Al and at least one other element selected from Si, B, Li, Na, K, Ba, Zn, Mn, Ca, Sr and Mg.

6. The tunable dielectric material of claim 1, wherein the low loss glass additive comprises borosilicate glass.

7. The tunable dielectric material of claim 1, wherein the low loss glass additive comprises lithia potash borosilicate glass.

8. The tunable dielectric material of claim 1, wherein the low loss glass additive comprises B, Ca and Al.

9. The tunable dielectric material of claim 1, wherein the low loss glass additive comprises from about 0.1 to about 60 weight percent of the material.

10. The tunable dielectric material of claim 1, wherein the low loss glass additive comprises from about 0.1 to about 25 weight percent of the material.

11. The tunable dielectric material of claim 1, wherein the low loss glass additive comprises from about 0.5 to about 15 weight percent of the material.

12. The tunable dielectric material of claim 1, wherein the low loss glass additive comprises at least about 2 weight percent of the material.

13. The tunable dielectric material of claim 1, wherein the low loss glass additive comprises at least about 3 weight percent of the material.

14. The tunable dielectric material of claim 1, wherein the low loss glass additive has a dielectric loss of less than about 0.003 at a frequency of 2 GHz.

15. The tunable dielectric material of claim 1, wherein the tunable dielectric ceramic is selected from barium strontium titanate, barium titanate, strontium titanate, barium calcium titanate, barium calcium zirconium titanate, lead titanate, lead zirconium titanate, lead lanthanum zirconium titanate, lead niobate, lead tantalate, potassium strontium niobate, sodium barium niobate/potassium phosphate, potassium niobate, lithium niobate, lithium tantalate, lanthanum tantalate, barium calcium zirconium titanate, sodium nitrate, and combinations thereof.

16. The tunable dielectric material of claim 1, wherein the tunable dielectric ceramic comprises barium strontium titanate.

17. The tunable dielectric material of claim 1, wherein the material further comprises a non-tunable dielectric ceramic comprising a metal oxide.

18. The tunable dielectric material of claim 1, wherein the material further comprises a non-tunable dielectric ceramic comprising a metal silicate.

19. The tunable dielectric material of claim 1, wherein the material further comprises at least one non-tunable dielectric ceramic comprising MgO, MgAl2O4, MgTiO3, Mg2SiO4, CaSiO3, MgSrZrTiO6, CaTiO3, Al2O3, SiO2, BaSiO3, SrSiO3, MgAl2O4, WO3, SnTiO4, ZrTiO4, CaSnO3, CaWO4, CaZrO3, MgTa2O6, MgZrO3, MnO2, PhO, Bi2O3 and/or La2O3.

20. The tunable dielectric material of claim 1, wherein the material further comprises at least one non-tunable dielectric ceramic comprising Mg2SiO4, CaSiO3, BaSiO3, SrSiO3, MgO, CaTiO3, MgZrSrTiO6, MgTiO3, MgAl2O4, MgTa2O6 and/or MgZrO3.

21. The tunable dielectric material of claim 1, wherein the tunable dielectric ceramic comprises barium strontium titanate and the low loss glass additive comprises B and at least one element selected from Ca, Al and Si.

22. The tunable dielectric material of claim 21, wherein the material further comprises at least one non-tunable dielectric ceramic comprising a metal oxide or a metal silicate.

23. The tunable dielectric material of claim 22, wherein the non-tunable dielectric ceramic comprises Mg2SiO4, CaSiO3, BaSiO3, SrSiO3, MgO, CaTiO3, MgZrSrTiO6, MgTiO3, MgAl2O4, MgTa2O6 and/or MgZrO3.

24. The tunable dielectric material of claim 1, wherein the material has a microwave loss of less than about 0.08 at a frequency of 2 GHz.

25. The tunable dielectric material of claim 1, wherein the material has a tunability of at least 5 percent at 4 V/micron.

26. The tunable dielectric material of claim 1, wherein the material has a breakdown strength of at least about 80 V/micron thickness.

27. The tunable dielectric material of claim 1, wherein the material has a sintering temperature of less than 1,200°

C.

28. The tunable dielectric material of claim 1, wherein the material has a sintering temperature of less than 1,100°

C.

29. The tunable dielectric material of claim 1, wherein the material has a sintering temperature of less than 1,000°

C.

30. A tunable device comprising:

a substrate; and

a tunable dielectric material deposited on the substrate, wherein the tunable dielectric material comprises a low loss glass additive.

31. The tunable device of claim 30, wherein the substrate comprises alumina, fosterite, zirconia or insulated metal.