Film bulk acoustic wave device

Patent 5789845 Issued on August 4, 1998. Estimated Expiration Date:

November 15, 2015. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

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Inventors

Application

No. 559706 filed on 11/15/1995

US Classes:

310/334, Acoustic wave type generator or receiver310/311, Piezoelectric elements and devices310/324Diaphragm

Examiners

Primary: Dougherty, Thomas M.

Attorney, Agent or Firm

Wolf, Greenfield & Sacks, P.C.

Foreign Patent References

0407848A2 EP 01/18/1991
0503892A1 EP 09/18/1992

International Class

H01L 029/66

Foreign Application Priority Data

1994-11-24 JP

Abstract

Embodiments of the present invention provide a small and well-characterized bulk acoustic wave device by fabricating a filter having a wide band width or a resonator having a wide oscillation frequency range together with a semiconductor circuit. In embodiments of the present invention, a bulk acoustic wave device comprises a semiconductor substrate having a dielectric substance layer thereon, the dielectric substance layer has a ground conductor layer thereon, the ground conductor layer has a piezoelectric ceramic thin film thereon and the piezoelectric ceramic thin film has a conductive electrode pattern thereon. The thickness of the piezoelectric ceramic thin film is more than ten times the thickness of the ground conductor layer, and the wave number of acoustic waves that propagate in a direction parallel to a surface of the piezoelectric ceramic thin film multiplied by the thickness of the piezoelectric ceramic thin film is less than 2.

Other References

Yoichi Miyasaka, Shigeki Hoshino & Sadayuki Takahashi "Advances in Structure and Fabrication Process For Thin Film Acoustic Resonator" 1987 Ultrasonics Symposium IEEE
Hiroaki Satoh, Mitoshi Suzuki, Chikau Takahashi, Chhouji Narahara and Yasuo Ebata "A 400 MHz One-Chip Oscillator Using an Air-Gap Type Thin Film Resonator" 1987 Ultrasonics Symposium IEEE
C. Vale, J. Rosenbaum, S. Horwitz, S. Krishnaswamy & R. Moore "FBAR Filters At Ghz Frequencies" 1990 IEEE Westinghouse Electric Corp
1987 IEEE, 41st Annual Frequency Control Symposium, "Thin File Resonator Technology", pp. 371-381
1987 IEEE Ultrasonics Symposium, "A 400 MHz One-chip oscillator using an Air-Gap type Think Film Resonator", pp. 363-36