Resonator with complementary oriented piezoelectric structure

Abstract

An acoustic resonator is provided, comprising a first piezoelectric layer (610A) of a material with a first crystallographic orientation and a second piezoelectric layer (610B) coupled to the first piezoelectric layer and comprising a material with a second crystallographic orientation, such that a piezoelectric tensor of the second piezoelectric layer has an opposite polarity to a piezoelectric tensor of the first piezoelectric layer. Furthermore, an interdigital transducer, IDT (638a, 638b), comprising nested fingers, is arranged on a surface of the first piezoelectric layer; and a first dielectric coating layer (612) is arranged over the IDT and the first piezoelectric layer.