BULK ACOUSTIC WAVER RESONATOR WITH MEANS FOR SUPPRESSION OF PASS-BAND RIPPLE IN BULK ACOUSTIC WAVE FILTERS

摘要

A bulk acoustic wave resonator comprising a substrate, a Bragg reflector, a top and a bottom electrode and a piezoelectric layer with means for suppression of the pass-band ripples in a bulk acoustic wave filter. The means for absorbing or scattering the spurious modes are a roughened rear side of the substrate, an absorbing layer disposed on the rear side of the substrate and/or an absorbing layer disposed on the front side of the substrate.