Abstract: The present disclosure relates to a bulk acoustic wave (BAW) resonator that includes a bottom electrode, a piezoelectric layer over the bottom electrode, and a top electrode structure with a top electrode and the dual-step BO ring structure. Herein, the dual-step BO structure is formed over the piezoelectric layer and about a periphery of the top electrode structure, such that a central portion of the piezoelectric layer is not covered by the dual-step BO structure. The dual-step BO structure is formed of an oxide material and includes an inner BO ring with a first height and an outer BO ring with a second height that is larger than the first height, such that the dual-step BO structure decreases in height toward the central portion of the piezoelectric layer. The top electrode is formed over the central portion of the piezoelectric layer and extends over the dual-step BO structure.

Abstract: The present disclosure relates to a bulk acoustic wave (BAW) resonator that includes a bottom electrode, a top electrode structure with a border ring (BO) structure, a piezoelectric layer sandwiched between the bottom electrode and the top electrode, and a reflector with a high acoustic impedance layer embedded in a low acoustic impedance region. Herein, the BO structure is formed about a periphery of the top electrode structure and defines a BO region of the BAW resonator. The high acoustic impedance layer is vertically underneath the bottom electrode and is separated from the bottom electrode by a first portion of the low acoustic impedance region. A width of the first high acoustic impedance layer is smaller than a width of the top electrode structure, such that the first high acoustic impedance layer does not extend completely through the BO region of the BAW resonator.

Abstract: An acoustic device includes a foundation structure and a transducer provided over the foundation structure. The foundation structure includes a piezoelectric layer between a top electrode and a bottom electrode. The piezoelectric layer has an active portion within an active region of the transducer, and a bi-polar border portion within a border region of the transducer. The piezoelectric material in the active portion has a first polarization. The bi-polar border portion has a first sub-portion and a second sub-portion, which resides either above or below the first sub-portion. The piezoelectric material in the first sub-portion has the first polarization, and the piezoelectric material in the second sub-portion has a second polarization, which is opposite the first polarization.

Abstract: Bulk acoustic wave (BAW) resonators, and particularly top electrodes with step arrangements for BAW resonators are disclosed. Top electrodes on piezoelectric layers are disclosed that include a border (BO) region with a dual-step arrangement where an inner step and an outer step are formed with increasing heights toward peripheral edges of the top electrode. Dielectric spacer layers may be provided between the outer steps and the piezoelectric layer. Passivation layers are disclosed that extend over the top electrode either to peripheral edges of the piezoelectric layer or that are inset from peripheral edges of the piezoelectric layer. Piezoelectric layers may be arranged with reduced thickness portions in areas that are uncovered by top electrodes. BAW resonators as disclosed herein are provided with high quality factors and suppression of spurious modes while also providing weakened BO modes that are shifted farther away from passbands of such BAW resonators.

Abstract: Bulk acoustic wave (BAW) resonators and particularly top electrodes with step arrangements for BAW resonators are disclosed. Top electrodes on piezoelectric layers are disclosed that include a border (BO) region with a dual-step arrangement where an inner step and an outer step are formed with increasing heights toward peripheral edges of the top electrode. Dielectric spacer layers may be provided between the outer steps and the piezoelectric layer. Passivation layers are disclosed that extend over the top electrode either to peripheral edges of the piezoelectric layer or that are inset from peripheral edges of the piezoelectric layer. Piezoelectric layers may be arranged with reduced thickness portions in areas that are uncovered by top electrodes. BAW resonators as disclosed herein are provided with high quality factors and suppression of spurious modes while also providing weakened BO modes that are shifted farther away from passbands of such BAW resonators.

Abstract: An acoustic device includes a foundation structure and a transducer provided over the foundation structure. The foundation structure includes a piezoelectric layer between a top electrode and a bottom electrode. The piezoelectric layer has an active portion within an active region of the transducer, and a bi-polar border portion within a border region of the transducer. The piezoelectric material in the active portion has a first polarization. The bi-polar border portion has a first sub-portion and a second sub-portion, which resides either above or below the first sub-portion. The piezoelectric material in the first sub-portion has the first polarization, and the piezoelectric material in the second sub-portion has a second polarization, which is opposite the first polarization.

Abstract: Bulk acoustic wave (BAW) resonators, and particularly top electrodes with step arrangements for BAW resonators are disclosed. Top electrodes on piezoelectric layers are disclosed that include a border (BO) region with a dual-step arrangement where an inner step and an outer step are formed with increasing heights toward peripheral edges of the top electrode. Dielectric spacer layers may be provided between the outer steps and the piezoelectric layer. Passivation layers are disclosed that extend over the top electrode either to peripheral edges of the piezoelectric layer or that are inset from peripheral edges of the piezoelectric layer. Piezoelectric layers may be arranged with reduced thickness portions in areas that are uncovered by top electrodes. BAW resonators as disclosed herein are provided with high quality factors and suppression of spurious modes while also providing weakened BO modes that are shifted farther away from passbands of such BAW resonators.

Abstract: An acoustic device includes a foundation structure and a transducer provided over the foundation structure. The foundation structure includes a piezoelectric layer between a top electrode and a bottom electrode. The piezoelectric layer has an active portion within an active region of the transducer, and a bi-polar border portion within a border region of the transducer. The piezoelectric material in the active portion has a first polarization. The bi-polar border portion has a first sub-portion and a second sub-portion, which resides either above or below the first sub-portion. The piezoelectric material in the first sub-portion has the first polarization, and the piezoelectric material in the second sub-portion has a second polarization, which is opposite the first polarization.

Abstract: Bulk acoustic wave (BAW) resonators, and particularly top electrodes with step arrangements for BAW resonators are disclosed. Top electrodes on piezoelectric layers are disclosed that include a border (BO) region with a dual-step arrangement where an inner step and an outer step are formed with increasing heights toward peripheral edges of the top electrode. Dielectric spacer layers may be provided between the outer steps and the piezoelectric layer. Passivation layers are disclosed that extend over the top electrode either to peripheral edges of the piezoelectric layer or that are inset from peripheral edges of the piezoelectric layer. Piezoelectric layers may be arranged with reduced thickness portions in areas that are uncovered by top electrodes. BAW resonators as disclosed herein are provided with high quality factors and suppression of spurious modes while also providing weakened BO modes that are shifted farther away from passbands of such BAW resonators.

Abstract: Embodiments provide a solidly-mounted bulk acoustic wave (BAW) resonator and method of making same. In embodiments, the BAW resonator may include a planarization portion in an inactive region of the BAW resonator that is coplanar with a piezoelectric layer of the BAW resonator in an active region of the BAW resonator. Other embodiments may be described and claimed.

Abstract: Bulk acoustic wave (BAW) resonators, and particularly shaped border (BO) rings for BAW resonators are disclosed. Top electrode arrangements are disclosed that include a BO ring arranged about a periphery of a top electrode, where the BO ring forms a top surface having a shape that is sloped or graded in comparison to planar surfaces of the top electrode. The top surface of the BO ring may be arranged such that a height of the top surface is graded in a descending manner toward a central region of the BAW resonator. BAW resonators as disclosed herein are provided with high quality factors and suppression of spurious modes while also providing reduced acoustic leakage and mode conversion.

Abstract: Bulk Acoustic Wave (BAW) resonators that include a modified outside stack portion and methods for fabricating such BAW resonators are provided. One BAW resonator includes a reflector, a bottom electrode, a piezoelectric layer, and a top electrode. An active region is formed where the top electrode overlaps the bottom electrode and an outside region surrounds the active region. The piezoelectric layer includes a top surface adjacent to the top electrode and a bottom surface adjacent to the bottom electrode. The piezoelectric layer further includes an outside piezoelectric portion in the outside region with a bottom surface in the outside region that is an extension of the bottom surface of the piezoelectric layer, and the outside piezoelectric portion includes an angled sidewall that resides in the outside region and extends from the top surface of the piezoelectric layer to the bottom surface of the outside piezoelectric portion in the outside region.

Abstract: Bulk acoustic wave (BAW) resonators, and particularly shaped border (BO) rings for BAW resonators are disclosed. Top electrode arrangements are disclosed that include a BO ring arranged about a periphery of a top electrode, where the BO ring forms a top surface having a shape that is sloped or graded in comparison to planar surfaces of the top electrode. The top surface of the BO ring may be arranged such that a height of the top surface is graded in a descending manner toward a central region of the BAW resonator. BAW resonators as disclosed herein are provided with high quality factors and suppression of spurious modes while also providing reduced acoustic leakage and mode conversion.

Abstract: Bulk acoustic wave (BAW) resonators, and particularly top electrodes with step arrangements for BAW resonators are disclosed. Top electrodes on piezoelectric layers are disclosed that include a border (BO) region with a dual-step arrangement where an inner step and an outer step are formed with increasing heights toward peripheral edges of the top electrode. Dielectric spacer layers may be provided between the outer steps and the piezoelectric layer. Passivation layers are disclosed that extend over the top electrode either to peripheral edges of the piezoelectric layer or that are inset from peripheral edges of the piezoelectric layer. Piezoelectric layers may be arranged with reduced thickness portions in areas that are uncovered by top electrodes. BAW resonators as disclosed herein are provided with high quality factors and suppression of spurious modes while also providing weakened BO modes that are shifted farther away from passbands of such BAW resonators.

Abstract: An acoustic device includes a foundation structure and a transducer provided over the foundation structure. The foundation structure includes a piezoelectric layer between a top electrode and a bottom electrode. The piezoelectric layer has an active portion within an active region of the transducer, and a bi-polar border portion within a border region of the transducer. The piezoelectric material in the active portion has a first polarization. The bi-polar border portion has a first sub-portion and a second sub-portion, which resides either above or below the first sub-portion. The piezoelectric material in the first sub-portion has the first polarization, and the piezoelectric material in the second sub-portion has a second polarization, which is opposite the first polarization.

Abstract: A Bulk Acoustic Wave (BAW) resonator with an electrically isolated Border (BO) ring is provided. One BAW resonator includes a bottom electrode and a piezoelectric layer over the bottom electrode and having a top surface with a first portion and second portion about the first portion. The BAW resonator also includes a top electrode over the first portion of the piezoelectric layer and a BO ring including a non-conductive portion that is over the second portion of the piezoelectric layer and adjacent to the piezoelectric layer. The BAW resonator may be a Solidly Mounted BAW (SMR-BAW) resonator or a Film BAW Resonator (FBAR). A radio frequency filter including a ladder configuration with the above BAW resonator as a series BAW resonator and methods for fabricating the above BAW resonator are also provided.

Abstract: Bulk Acoustic Wave (BAW) resonators with a Border (BO) ring and an inner ring are provided. One BAW resonator includes a bottom electrode, a piezoelectric layer over the bottom electrode, and a top electrode over the piezoelectric layer in which an active region is formed where the top electrode and the bottom electrode overlap. The top electrode includes a BO ring extending about a periphery of the active region and an inner ring inside of and spaced apart from the BO ring. The BO ring is a mass loading of a first portion of the top electrode and the inner ring is a mass unloading of a second portion of the top electrode. Various methods include fabricating a BAW resonator with a top electrode including a mass loading BO ring and a mass unloading inner ring spaced apart from the mass loading BO ring.

Abstract: Embodiments provide a solidly-mounted bulk acoustic wave (BAW) resonator and method of making same. In embodiments, the BAW resonator may include a planarization portion in an inactive region of the BAW resonator that is coplanar with a piezoelectric layer of the BAW resonator in an active region of the BAW resonator. Other embodiments may be described and claimed.

Abstract: Embodiments provide a solidly-mounted bulk acoustic wave (BAW) resonator and method of making same. In embodiments, the BAW resonator may include a planzarization portion in an inactive region of the BAW resonator that is coplanar with a piezoelectric layer of the BAW resonator in an active region of the BAW restonator. Other embodiments may be described and claimed.

Abstract: Bulk Acoustic Wave (BAW) resonators with a Border (BO) ring and an inner ring are provided. One BAW resonator includes a bottom electrode, a piezoelectric layer over the bottom electrode, and a top electrode over the piezoelectric layer in which an active region is formed where the top electrode and the bottom electrode overlap. The top electrode includes a BO ring extending about a periphery of the active region and an inner ring inside of and spaced apart from the BO ring. The BO ring is a mass loading of a first portion of the top electrode and the inner ring is a mass unloading of a second portion of the top electrode. Various methods include fabricating a BAW resonator with a top electrode including a mass loading BO ring and a mass unloading inner ring spaced apart from the mass loading BO ring.