FBAR characteristics with AlN film using MOCVD method and Ru/Ta electrode

Y. Aota, S. Tanifuji, H. Oguma, S. Kameda, H. Nakase, T. Takagi, K. Tsubouchi

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

5 Citations (Scopus)


Film bulk acoustic resonator (FBAR) was fabricated using high oriented A1N(0002) film obtained through the metal-organic chemical vapor deposition (MOCVD) method. We used the Ru/Ta bottom electrode to improve the FBAR resonant characteristics because Ru has a high acoustic impedance and a hexagonal crystalline that is effective to obtaine the high oriented AlN(0002) film. The Ru/Ta electrode had good characteristics under 1100°C in points of the full width at half maximum (FWHM) of Ru(0002), the surface roughness and the electrode resistivity. The evaluated FWHM of AlN(0002) on Ru/Ta at 1050°C was exellent value of 1.2°. The resonant frequency and anti-resonant frequency of the fabricated FBAR using the Ru/Ta bottom electrode were 5.217GHz and 5.479GHz, respectively. The resistance of the FBAR electrodes and of the series-resonance part in modified Butterworth Van Dyke (MBVD) equivalent circuit were improved to 4.3 Ω from 7.0 Ω and to 0.5 Ω from 3.0 Ω compared to the results of previous Mo bottom electrode, respectively. The effective electro-mechanical coupling coefficient (ke f f 2) of the fabricated FBAR was exellent value of 7.0% and the evaluated Qr was 329. We successfully fabricated the FBAR with the small insertion loss and the large ke f f2 using the Ru/Ta bottom electrode and high oriented AlN(0002) film.

Original languageEnglish
Title of host publication2007 IEEE Ultrasonics Symposium Proceedings, IUS
Number of pages4
Publication statusPublished - 2007
Event2007 IEEE Ultrasonics Symposium, IUS - New York, NY, United States
Duration: 2007 Oct 282007 Oct 31

Publication series

NameProceedings - IEEE Ultrasonics Symposium
ISSN (Print)1051-0117


Conference2007 IEEE Ultrasonics Symposium, IUS
Country/TerritoryUnited States
CityNew York, NY


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