Patent ID: 6424237
Filing Date: 2002-07-23
Classification: H03H,Y10T

Abstract:
An acoustic resonator comprising:a substrate having a depression formed in a top surface thereof; a first electrode disposed on the top surface of the substrate and over the depression, the first electrode extending beyond a plurality of edges of the depression by a first distance to define a first region therebetween; a piezoelectric material disposed on the top surface of the substrate and over the first electrode; and a second electrode disposed on the piezoelectric material and including a portion located above the depression, the portion located above the depression having at least one edge that is offset from a corresponding edge of the depression by a second distance to define a second region therebetween, the second region having an impedance that differs from an impedance of the first region, wherein an overlap of the first electrode, the piezoelectric material and the second electrode forms an acoustic cavity of the resonator, and the first and second distances are chosen such that reflections from the edges of the first and second regions will constructively interfere.