Bulk acoustic wave resonator structure for use in e.g. voltage transformer, has top electrode arranged over piezoelectric layer, and bridge formed in layer, where bridge is surrounded by piezoelectric material of layer

摘要

The structure has a bulk acoustic wave (BAW) resonator and a bottom electrode (107) arranged over a substrate (105). A piezoelectric layer (108) is arranged over the electrode. A top electrode (101) is arranged over the layer. A trapezoidal cross-sectional shaped bridge (402') is formed in the layer and surrounded by piezoelectric material of the layer. The bridge comprises an unfilled bridge that contains air, and a filled bridge that contains a dielectric material or metal. An acoustic coupling layer is formed over the top electrode. The resonator is a double bulk acoustic resonator (400) or thin-film bulk acoustic resonator.