Surface acoustic wave device, electronic component using the device, and composite module

摘要

A surface acoustic wave device includes a piezoelectric substrate and an electrode provided on the substrate. The electrode includes a first metal layer provided on the piezoelectric substrate and having a trapezoid shape in the cross section and a second metal layer provided over the piezoelectric substrate at the same position as the first metal layer over the piezoelectric substrate. By controlling the shape of side surfaces of the electrode, the surface acoustic wave device hardly vary in a propagation frequency.