Aspects of this disclosure relate to method of manufacturing a bulk acoustic wave device. The method can include providing a bulk acoustic wave device structure including a first piezoelectric layer and forming a second piezoelectric layer over the first piezoelectric layer by atomic layer deposition. The second piezoelectric layer can have an opposite polarization relative to the first piezoelectric layer.

Aspects of this disclosure relate to method of manufacturing a bulk acoustic wave device. The method can include providing a bulk acoustic wave device structure including a first piezoelectric layer and forming a second piezoelectric layer over the first piezoelectric layer by atomic layer deposition. The second piezoelectric layer can have an opposite polarization relative to the first piezoelectric layer.

Aspects of this disclosure relate to a bulk acoustic wave device with a plurality of piezoelectric layers having at least one polarization inversion. The bulk acoustic wave device can include a first piezoelectric layer and a second piezoelectric layer over the first piezoelectric layer. The second piezoelectric layer can be formed by atomic layer deposition. The second piezoelectric layer can have an opposite polarization relative to the first piezoelectric layer. Related filters, multiplexers, packaged radio frequency modules, radio frequency front ends, wireless communication devices, and methods are disclosed.

Aspects of this disclosure relate to a bulk acoustic wave device with a plurality of piezoelectric layers having at least one polarization inversion. The bulk acoustic wave device can include a first piezoelectric layer and a second piezoelectric layer over the first piezoelectric layer. The second piezoelectric layer can be formed by atomic layer deposition. The second piezoelectric layer can have an opposite polarization relative to the first piezoelectric layer. Related filters, multiplexers, packaged radio frequency modules, radio frequency front ends, wireless communication devices, and methods are disclosed.

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.

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.

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.

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.

A vibration element includes a base and a vibrating arm extending from the base. The vibrating arm includes an arm positioned between the base and a weight. A weight film is disposed on the weight. The weight has a first principal surface and a second principal surface in a front and back relationship with respect to a center plane of the arm. A center of gravity of the weight is located between the first principal surface and the center plane of the arm. A center of gravity of the weight film is located between the second principal surface and the center plane of the arm.

A vibration element includes a base and a vibrating arm extending from the base. The vibrating arm includes an arm positioned between the base and a weight. A weight film is disposed on the weight. The weight has a first principal surface and a second principal surface in a front and back relationship with respect to a center plane of the arm. A center of gravity of the weight is located between the first principal surface and the center plane of the arm. A center of gravity of the weight film is located between the second principal surface and the center plane of the arm.