Low Loss Intermediate-Frequency Resonator Filter Using Shear Horizontal Type Leaky Surface Acoustic Wave on $\alpha$-Phase Heavy Metal Film/Quartz

概要

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By applying a new shear horizontal (SH)-type leaky surface acoustic wave (LSAW) excited by interdigital transducers (IDTs) and reflectors made of Ta or W on an ST-cut 90°X-propagation (direction perpendicular to $X$-axis) quartz substrate, we succeeded in fabricating very small resonator filters (1/5–1/4 of conventional device sizes). However, the Ta and W films used in our filters were $\beta$-Ta and $\beta$-W, which have resistances higher than that of an Al film. $\alpha$-Ta and $\alpha$-W films with very low resistivities have been successfully deposited in place of $\beta$-Ta and $\beta$-W films. The insertion loss of resonator filters consisting Ta- or W-electrode/ST-90°X quartz has been improved by 1.5–8 dB using the $\alpha$-Ta or the $\alpha$-W film electrode.
Published by the Japan Society of Applied Physics through the Institute of Pure and Applied Physicsの論文
2004-05-15