Patent ID: 8378553
Filing Date: 2013-02-19
Classification: H01L,H03H

Abstract:
1. A surface acoustic wave device comprising: a piezoelectric substrate of a single crystal having symmetry 3 m for providing propagation of leaky waves with quasi-SH polarization and squared electromechanical coupling coefficient exceeding 5%; an electrode pattern disposed on a surface of the piezoelectric substrate, wherein the electrode pattern includes electrodes having a thickness and Cu as a primary electrode material, and wherein the electrode pattern forms a resonator; a dielectric overlay of silicon oxide having positive TCF, the dielectric overlay disposed between and over electrodes of the electrode pattern, wherein the dielectric overlay includes a generally flattened surface, the dielectric overlay having a thickness up to 30% λ, and wherein the thickness of the dielectric overlay, the thickness of the electrodes, and a rotation angle of the piezoelectric substrate are configured such that a propagation loss of the device at a resonant frequency is substantially equal to a propagation loss at an anti-resonant frequency, and do not exceed 0.02 dB/λ, wherein the piezoelectric substrate includes LiTaO3 having an orientation defined by Euler angles (0±3°, μ, 0±3°), with the rotation angle μ=μ′−90°, where μ′ ranges from about 36° to about 54°, wherein the thickness of the electrodes range from 0.1% λ to 10% λ, and wherein the Euler angles, which determine orientation of the piezoelectric substrate are dependent on the thickness of the electrodes and the thickness of the dielectric overlay, wherein μ′=μ where h h and, wherein normalized thicknesses, h Cu and h SiOx , are specified in % λ.