Jpn. J. Appl. Phys. 47 (2008) pp. 4007-4010  |Previous Article| |Next Article|  |Table of Contents|
|Full Text PDF (304K)| |Buy This Article|

Development of an X-Band Filter Using Air-Gap-Type Film Bulk Acoustic Resonators

Masanori Ueda^1,3, Motoaki Hara¹, Shinji Taniguchi², Tsuyoshi Yokoyama¹, Tokihiro Nishihara², Ken-ya Hashimoto³, and Yoshio Satoh¹

(Received November 20, 2007; accepted January 15, 2008; published online May 23, 2008)

We have developed an X-band filter utilizing air-gap-type film bulk acoustic resonators (FBARs). The air-gap structure is simple and cost-effective. Results from both simulations and experiments demonstrate that a dome-shaped air gap was formed between the substrate surface and the bottom electrode and that an air-gap-type FBAR structure was possible. The air gap can be formed on the flat substrate using stress control of piezoelectric and metal films without using a thick sacrificial layer. As a result, the fabricated X-band FBAR operated successfully with a k_eff² of 6.30%, a resonance Q of 246, and an antiresonance Q of 462. The fabricated filter had a center frequency of 9.07 GHz, a fractional bandwidth of 3.1% and a minimum insertion loss of 1.7 dB.

URL: http://jjap.jsap.jp/link?JJAP/47/4007/
DOI: 10.1143/JJAP.47.4007

References | Citing Articles (14)

1. O. Ikata, T. Miyashita, T. Matsuda, T. Nishihara, and Y. Satoh: IEEE Proc. Ultrasonics Symp., 1992, p. 111.
2. T. Matsuda, J. Tsutsumi, S. Inoue, Y. Iwamoto, Y. Satoh, M. Ueda, and O. Ikata: IEEE Proc. Ultrasonics Symp., 2002, p. 68.
3. M. Kadota: Jpn. J. Appl. Phys. 44 (2005) 4285[JSAP].
4. T. Shiba, T. Ishizuka, S. Ikeda, N. Kamogawa, N. Hosaka, T. Takagi, M. Katsugishi, and M. Hikita: Jpn. J. Appl. Phys. 42 (2003) 3148[JSAP].
5. P. Bradley, R. Ruby, A. Barfknecht, F. Geefay, C. Han, G. Gan, Y. Oshmyansky, and J. D. Larson, III: IEEE Proc. Ultrasonics Symp., 2002, p. 907.
6. R. Aigner: IEEE MEE-S Int. Microwave Symp., 2004, WMB-14.
7. K. Nakamura and H. Kanbara: Proc. IEEE Frequency Control Symp., 1998, p. 876.
8. K. M. Lakin: Proc. IEEE Ultrasonics Symp., 1999, p. 895.
9. Y. Satoh, T. Nishihara, T. Yokoyama, M. Ueda, and T. Miyashita: Jpn. J. Appl. Phys. 44 (2005) 2883[JSAP].
10. T. Nishihara, T. Yokoyama, T. Miyashita, and Y. Satoh: Proc. IEEE Ultrasonics Symp., 2002, p. 969.
11. T. Yokoyama, T. Nishihara, S. Taniguchi, M. Iwaki, Y. Satoh, M. Ueda, and T. Miyashita: Proc. IEEE Frequency Control Symp., 2004, p. 429.
12. R. Ruby, P. Bradley, Y. Oshmyansky, and A. Chien: Proc. IEEE Ultrasonics Symp., 2001, p. 813.
13. M. Ueda, T. Nishihara, J. Tsutsumi, S. Taniguchi, T. Yokoyama, S. Inoue, T. Miyashita, and Y. Satoh: IEEE MTT-S Int. Microwave Symp., 2005, TU3D-1.
14. J. Tsutsumi, M. Iwaki, Y. Iwamoto, T. Yokoyama, T. Sakashita, T. Nishihara, M. Ueda, and Y. Satoh: Proc. IEEE Ultrasonics Symp., 2005, p. 93.
15. M. Ueda, T. Nishihara, J. Tsutsumi, T. Yokoyama, M. Iwaki, and Y. Satoh: 35th EM Symp., 2005, p. 35 [in Japanese].
16. J. Larson, P. Bradley, S. Wartenberg, and R. Ruby: Proc. IEEE Ultrasonics Symp., 2000, p. 863.
17. M. Ueda, T. Nishihara, S. Taniguchi, T. Yokoyama, J. Tsutsumi, M. Iwaki, and Y. Satoh: Jpn. J. Appl. Phys. 46 (2007) 4642[JSAP].
18. R. B. Stokes and J. D. Crawford: IEEE Trans. Microwave Theory Tech. 41 (1993) 1075.
19. R. Lanz and P. Muralt: IEEE Trans. Ultrason. Ferroelectr. Freq. Control. 52 (2005) 937.
20. K. Yamanouchi, Y. Satoh, H. Isono, and D. Kawaski: Proc. IEEE Ultrasonics Symp., 2005, p. 2170.
21. H. Satoh, H. Suzuki, C. Takahashi, C. Narahara, and Y. Ebata: Proc. IEEE Ultrasonics Symp., 1987, p. 363.
22. K. Yamanouchi and M. Oba: Proc. IEEE Ultrasonics Symp., 1987, p. 415.
23. M. Hara and M. Esashi: 2nd Int. Symp. Acoustic Wave Devices for Future Mobile Communication Systems, 2004, p. 115.
24. S. Taniguchi, T. Yokoyama, M. Iwaki, T. Nishihara, M. Ueda, and Y. Satoh: to be published in Proc. IEEE Ultrasonics Symp., 2007.
25. M. Hara, T. Yokoyama, M. Ueda, and Y. Satoh: to be published in Proc. IEEE Ultrasonics Symp., 2007.