Reduction of Transverse Surface Acoustic Wave Leakage in Resonator on Al/42° YX-LiTaO

概要

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In this paper, we propose a new structure for reducing the extent of transverse surface acoustic wave (SAW) leakage for the SAW resonator on a 42° YX-LiTaO<inf>3</inf>substrate. Such leakage occurs from the interdigital region toward the busbar region in the SAW resonators. The new structure has a Ta<inf>2</inf>O<inf>5</inf>film outside the interdigital region. This structure can make the SAW velocity in the busbar region lower than the velocity in the interdigital region. Therefore, the new structure could reduce the extent of leakage, and contribute to confine the SAW energy in the interdigital region. This structure was applied in SAW resonators and ladder-type SAW filters fabricated on a 42° YX-LiTaO<inf>3</inf>substrate. The insertion loss could be improved by suppressing transverse SAW leakage. This technique could be applied to the fabrication of the filters and duplexers using leaky SAW on a 42° YX-LiTaO<inf>3</inf>substrate, and the SAW devices could exhibit excellent performance.
2013-07-25