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Image Number 13 for United States Patent #8018122.
An SH wave type surface acoustic wave device includes a piezoelectric substrate and an IDT electrode provided on the piezoelectric substrate and constituted of Al or an alloy mainly containing Al and that uses a SH wave as an excitation wave. The piezoelectric substrate is a crystal plate in which a cut angle .theta. of a rotary Y cut quartz substrate is set in a range of -64.0.degree.<.theta.<-49.3.degree. in a counter-clockwise direction from a crystal axis Z and in which a surface acoustic wave propagation direction is set at 90.degree..+-.5.degree. with respect to a crystal axis X. An electrode film thickness H/.lamda. standardized by a wavelength of the IDT electrode is 0.04<H/.lamda.<0.12, where .lamda. is a wavelength of the surface acoustic wave to be excited, and a main surface of the piezoelectric substrate is etched by a thickness of 0.002 .mu.m or more.
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