Abstract: Systems and techniques are described herein for using aluminum scandium nitride based electro-optical modulators. For example, a device or apparatus can include an optical waveguide comprising aluminum scandium nitride (AlScN) formed as part of a piezoelectric layer having an axis from a first side of the waveguide to a second side of the waveguide. The device or apparatus can further include an electrical signal line formed on the first side of the waveguide and a reference node formed on the second side of the waveguide.

Abstract: An apparatus is disclosed for implementing a microacoustic filter with a cavity stack. In an example aspect, the apparatus includes a microacoustic filter with an electrode structure, a cavity stack, a buffer layer, and a piezoelectric layer. The cavity stack comprises a conductive layer, a substrate layer, and at least two pillars extending past a plane defined by a surface of the substrate layer and towards the conductive layer to form a cavity between the substrate layer and the conductive layer. The buffer layer is disposed between the conductive layer of the cavity stack and the electrode structure. The piezoelectric layer is disposed between the buffer layer and the electrode structure.

Abstract: An apparatus is disclosed for implementing a microacoustic filter with an acoustically-decoupled electrode structure. In an example aspect, the apparatus includes the microacoustic filter with a piezoelectric layer, a substrate, and an electrode structure. The piezoelectric layer has a crystalline structure operative to laterally excite a plate mode. The electrode structure is positioned between the piezoelectric layer and the substrate and has a has a first surface that faces the piezoelectric layer. The microacoustic filter also includes at least one spacer extending from the substrate past a plane defined by the first surface of the electrode structure and towards the piezoelectric layer to form a cavity between the electrode structure and the piezoelectric layer.

Abstract: Disclosed are polarization-inverted higher-order plate-mode resonators and methods for making the same. In an aspect, a plate-mode resonator includes a first piezoelectric layer having a first crystal orientation specified by a first set of Euler angles ?1, ?1, and ?1, a dielectric layer disposed on a top surface of the first piezoelectric layer, a second piezoelectric layer, disposed on a top surface of the dielectric layer, having a second crystal orientation specified by a second set of Euler angles ?2, ?2, and ?2, wherein az is approximately equal to ?1, wherein a difference between ?2 and ?1 is approximately 180 degrees, and wherein ?2 is approximately equal to ?1, and a metallization structure disposed on a top surface of the second piezoelectric layer, the metallization structure comprising at least one interdigital transducer.

Abstract: A bulk acoustic wave resonator device comprises bottom and top electrodes (120, 360). A piezoelectric layer (355) sandwiched therebetween has a thickness in the active resonator area different from the thickness in the surrounding area. A method of manufacturing the device comprises a bonding of a piezoelectric wafer to a carrier wafer and splitting a portion of the piezoelectric wafer by an ion-cut technique. Different thicknesses of the piezoelectric layer in the active area and the surrounding area are achieved by implanting ions at different depths.

Abstract: A BAW resonator comprises a bottom electrode, a piezoelectric layer and a top electrode. A top electrode connection is arranged in a plane above the top electrode. For doing this a spacer is arranged on the top electrode. A capping layer is sitting on the spacer distant from the top electrode such that an air-filled gap to the top electrode is kept. The top electrode connection can now be arranged above the capping layer. An electrically conductive path connects the top electrode and the top electrode connection. Such a resonator needs only one lateral design and can provide a low-ohmic interconnection of resonators e.g. in a filter circuit.

Abstract: A bulk acoustic wave (BAW) device comprises a layer stack including first and second electrodes, a first piezoelectric layer between the electrodes, and a second piezoelectric layer between the first piezoelectric layer and the second electrode. A polarization of a crystal structure of the second piezoelectric layer is opposite to a polarization of a crystal structure of the first piezoelectric layer to achieve higher order resonant frequencies in the BAW device by means other than merely thinning layers in the layer stack. In some examples, the BAW device is a two-terminal device and does not include a metal layer configured to be a third electrode. In some examples, the BAW device includes at least one intermediate layer between the first and second piezoelectric layers, and a total combined thickness of the at least one intermediate layer is less than 4% of a total thickness of the layer stack.

Abstract: A bulk acoustic wave resonator device comprises bottom and top electrodes (120, 360). A piezoelectric layer (355) sandwiched therebetween has a thickness in the active resonator area different from the thickness in the surrounding area. A method of manufacturing the device comprises a bonding of a piezoelectric wafer to a carrier wafer and splitting a portion of the piezoelectric wafer by an ion-cut technique. Different thicknesses of the piezoelectric layer in the active area and the surrounding area are achieved by implanting ions at different depths.

Abstract: An apparatus is disclosed for implementing a microacoustic filter with a cavity stack. In an example aspect, the apparatus includes a microacoustic filter with an electrode structure, a cavity stack, a buffer layer, and a piezoelectric layer. The cavity stack comprises a conductive layer, a substrate layer, and at least two pillars extending past a plane defined by a surface of the substrate layer and towards the conductive layer to form a cavity between the substrate layer and the conductive layer. The buffer layer is disposed between the conductive layer of the cavity stack and the electrode structure. The piezoelectric layer is disposed between the buffer layer and the electrode structure.

Abstract: A bulk acoustic wave (BAW) device with resonance-tuned layer stack is disclosed. The BAW device includes two acoustic resonators with top electrodes in different regions on a top side of a piezoelectric layer. The BAW device includes an acoustic mirror on a bottom side of the piezoelectric layer and a bottom electrode between the acoustic mirror and the piezoelectric layer. The piezoelectric layer includes a recess in a second region on the bottom side of the piezoelectric layer. The bottom electrode is disposed in the recess on the bottom side of the piezoelectric layer. A distance between a first top electrode in a first region and the bottom electrode may be greater than a distance between a second top electrode in the second region and the bottom electrode.

Abstract: An apparatus is disclosed for partially suspending a piezoelectric layer using a dielectric. In an example aspect, the apparatus includes a microacoustic filter with a substrate layer, a piezoelectric layer, an electrode structure that is in contact with the piezoelectric layer, and a dielectric. The electrode structure includes multiple fingers arranged across a plane having a first axis that is perpendicular to the multiple fingers and a second axis that is parallel to the multiple fingers. The dielectric is configured to separate the piezoelectric layer from the substrate layer and define a cavity between the piezoelectric layer and the substrate layer. The dielectric is also configured to support the piezoelectric layer across at least three points along the first axis.

Abstract: A BAW resonator (BAWR) with improved power durability and improved heat resistance is provided. The resonator comprises a layer stack with a piezoelectric material (PM) between a bottom electrode (ELI) and a top electrode (EL2) and a shunt path parallel (PCPP) to the layer stack provided to enable an RF signal to bypass the layer stack, e.g. to ground (GND). The shunt path (PCPP) has a temperature dependent conductance with a negative temperature coefficient, NTC, of resistance. When the temperature of the device rises due to high power operation, currents that would otherwise permanently damage the device are shunted to ground or another dedicated terminal by the temperature dependent shunt path. Upon cooling down normal operation is resumed.

Abstract: Certain aspects of the present disclosure can be implemented in an electroacoustic device. The electroacoustic device generally includes a substrate and one or more resonator structures disposed above the substrate. In some cases, each resonator structure of the one or more resonator structures includes a bulk acoustic resonator, an acoustic mirror disposed below the bulk acoustic resonator, and one or more porous material layers disposed below the acoustic mirror and above the substrate.

Abstract: In at least one embodiment, the electric component comprises a first BAW-resonator (1), a second BAW-resonator (2) electrically connected to the first BAW-resonator and a carrier substrate (3) with a top side (30) on which the BAW-resonators are arranged. The first and the second BAW-resonator each comprise a bottom electrode (11,21) and a top electrode (12,22). The bottom electrodes are in each case located between the carrier substrate and the respective top electrode. A first piezoelectric layer (13) is arranged between the top electrode and the bottom electrode of the first BAW-resonator and laterally protrudes from the first BAW-resonator. The second BAW-resonator is mounted on the first piezoelectric layer in a region laterally next to the first BAW-resonator and comprises a second piezoelectric layer (23) between its top electrode and its bottom electrode. The two piezoelectric layers may have different thickness to realize resonators with different resonance frequencies on the same die.

Abstract: A BAW resonator with an improved lateral energy confinement is provided. The resonator has a bottom electrode in a bottom electrode layer, a top electrode in a top electrode layer and a piezoelectric layer between the bottom electrode layer and the top electrode layer. The piezoelectric layer comprises piezoelectric materials of different piezoelectric polarities.

Abstract: A BAW device comprises a first BAW resonator (1) and a second BAW resonator (2). The first BAW resonator and the second BAW resonator each comprise a first electrode (11, 21), a second electrode (12, 22) and a piezoelectric layer (13, 23) being arranged in each case between the first electrode and the second electrode of the associated BAW resonator. The first electrodes, the second electrodes and the piezoelectric layers of both BAW resonators are designed essentially identically. A first conductor track (24) extends from the first electrode of the second BAW resonator to a third electric element (3) of the BAW device and electrically connects said first electrode with said third electric element. A first dummy conductor track (14) extends from the first electrode of the first BAW resonator, is electrically connected to said first electrode and, apart from said first electrode, is not electrically connected to any further electric element.

Abstract: In certain aspects, a method for reducing coupling coefficient variation includes receiving one or more measured coupling coefficients of one or more acoustic resonators, determining a coupling coefficient change based on the one or more measured coupling coefficients, and determining a change in a dimension of a lateral feature based on the determined coupling coefficient change.

Abstract: A micro-acoustic device comprises a confinement structure (CS) adapted to block propagation of acoustic waves of an acoustic wave resonator (TEL, PL, BEL; ES) at an operation frequency of the device to confine the acoustic waves to the acoustic path or the acoustic volume. It is proposed to use a phononic crystal material for producing the confinement structure.

Abstract: A BAW resonator comprises a bottom electrode, a piezoelectric layer and a top electrode. A top electrode connection is arranged in a plane above the top electrode. For doing this a spacer is arranged on the top electrode. A capping layer is sitting on the spacer distant from the top electrode such that an air-filled gap to the top electrode is kept. The top electrode connection can now be arranged above the capping layer. An electrically conductive path connects the top electrode and the top electrode connection. Such a resonator needs only one lateral design and can provide a low-ohmic interconnection of resonators e.g. in a filter circuit.

Abstract: It is proposed to enhance the bandwidth of a SMR BAW resonator (TE,PL,BE) by circuiting it with a planar coil (WG1, WG2) that is realized in a high impedance layer (HI) of the Bragg mirror (BM) or in an additional metal layer below the Bragg mirror.