Abstract: A bulk acoustic wave resonator configured as a capacitor has a piezoelectric structure including a mesa region suspended above a substrate to define a cavity. The piezoelectric structure includes a perimeter region surrounding a perimeter of the mesa region with a sloping portion that gradually slopes towards the substrate and a connecting portion proximate the substrate that supports the piezoelectric structure with respect to the substrate. The piezoelectric structure incudes a bottom electrode layer, a top electrode layer, and a piezoelectric layer therebetween. An overlapping region where the bottom electrode layer and the top electrode layer overlap extends across at least a width of the mesa region between opposing sides of the perimeter region.

Abstract: The present disclosure provides a bulk acoustic wave resonator comprising a piezoelectric layer and a top electrode disposed on a first surface of the piezoelectric layer. The bulk acoustic wave resonator has a central region, a first outer region, and a first raised frame region between the central region and the first outer region. The top electrode has a first thickness within the central region, a second thickness within the first raised frame region, and a third thickness within the first outer region, the second thickness being greater than both the first thickness and the third thickness. A die, filter, radio-frequency module and wireless mobile device are also provided.

Abstract: A bulk acoustic wave resonator having a central region, an outer region, and a raised frame region between the central region and the outer region is disclosed. The bulk acoustic wave resonator can include a piezoelectric layer and a top electrode over the piezoelectric layer. The top electrode is disposed at least in the central region, the outer region, and the raised frame region. The top electrode is configured such that a resonant frequency in the outer region is higher than a resonant frequency in the central region.

Abstract: A bulk acoustic wave resonator having a central region, an outer region, and a raised frame region between the central region and the outer region is disclosed. The bulk acoustic wave resonator can include a piezoelectric layer and a top electrode over the piezoelectric layer. The top electrode is disposed at least in the central region, the outer region, and the raised frame region, the top electrode including a first layer and a second layer. A material of the first layer is different from the material of the second layer.