SURFACE ACOUSTIC WAVE DEVICE AND ITS MANUFACTURE METHOD, AND ELECTRONIC PART USING IT

摘要

A surface acoustic wave (SAW) device includes a piezoelectric substrate, and on this substrate there are provided comb electrodes for forming an inter digital transducer (IDT), reflector electrodes placed closely along a traveling direction of a surface wave generated by the IDT, and a frame-like short-circuited auxiliary electrode having a width varying depending on its portions. This structure allows to uniform electric charges overall the electrode-surfaces, where the electric charges are generated in a heat treatment applied to the piezoelectric substrate during the manufacturing of the SAW device. Thus even after the device is diced into pieces, this structure can prevent damages of the electrodes or degradation in electrical properties due to an electric discharge generated by accumulated electric charges caused by pyroelectricity of the substrate.