Deposition of Highly Oriented Ta2O5 Piezoelectric Thin Films on Silicon for Fabricating Film Bulk Acoustic Resonator Structure by RF Magnetron Sputtering

作者：Kakio Shoji^*; Tsuchiya Akinori; Nakagawa Yasuhiko

来源：Japanese Journal of Applied Physics, 2011, 50(7): 07HD09.

DOI：10.1143/JJAP.50.07HD09

X-axis-oriented tantalum pentoxide (Ta2O5) piezoelectric thin films were deposited on Si using an RF magnetron sputtering system with the aim of obtaining a film bulk acoustic resonator (FBAR) structure. First, the degree of orientation and the coupling factor K-2 for the surface acoustic wave were evaluated. The K-2 of the first mode of the Ta2O5 thin film deposited on the unprocessed Si(100) was almost the same as that of the zeroth mode of the Ta2O5 thin film/SiO2 glass substrate for a similar thickness. However, the K-2 of the Ta2O5 thin film deposited on a silicon oxide layer formed on the Si was small because the (200) plane spacing slightly increased. Then, a process in which the Ta2O5 thin film itself was used as an etch stop layer was adopted and an FBAR structure was fabricated. The resonance response corresponding to a longitudinal bulk wave was observed.

• 出版日期2011-7