A method of manufacture for an acoustic resonator or filter device. In an example, the present method can include forming metal electrodes with different geometric areas and profile shapes coupled to a piezoelectric layer overlying a substrate. These metal electrodes can also be formed within cavities of the piezoelectric layer or the substrate with varying geometric areas. Combined with specific dimensional ratios and ion implantations, such techniques can increase device performance metrics. In an example, the present method can include forming various types of perimeter structures surrounding the metal electrodes, which can be on top or bottom of the piezoelectric layer. These perimeter structures can use various combinations of modifications to shape, material, and continuity. These perimeter structures can also be combined with sandbar structures, piezoelectric layer cavities, the geometric variations previously discussed to improve device performance metrics.

A method of manufacture for an acoustic resonator or filter device. In an example, the present method can include forming metal electrodes with different geometric areas and profile shapes coupled to a piezoelectric layer overlying a substrate. These metal electrodes can also be formed within cavities of the piezoelectric layer or the substrate with varying geometric areas. Combined with specific dimensional ratios and ion implantations, such techniques can increase device performance metrics. In an example, the present method can include forming various types of perimeter structures surrounding the metal electrodes, which can be on top or bottom of the piezoelectric layer. These perimeter structures can use various combinations of modifications to shape, material, and continuity. These perimeter structures can also be combined with sandbar structures, piezoelectric layer cavities, the geometric variations previously discussed to improve device performance metrics.

A method of manufacture for an acoustic resonator or filter device. In an example, the present method can include forming metal electrodes with different geometric areas and profile shapes coupled to a piezoelectric layer overlying a substrate. These metal electrodes can also be formed within cavities of the piezoelectric layer or the substrate with varying geometric areas. Combined with specific dimensional ratios and ion implantations, such techniques can increase device performance metrics. In an example, the present method can include forming various types of perimeter structures surrounding the metal electrodes, which can be on top or bottom of the piezoelectric layer. These perimeter structures can use various combinations of modifications to shape, material, and continuity. These perimeter structures can also be combined with sandbar structures, piezoelectric layer cavities, the geometric variations previously discussed to improve device performance metrics.

An acoustic wave filter device is disclosed. The device includes an acoustic wave filter element, and a first resonator and a second resonator coupled to the acoustic wave filter element. The acoustic wave filter element includes interdigited input electrodes and output electrodes located on a top surface of a piezoelectric layer. Each of the first and the second resonators includes a top electrode on the top surface, and a bottom electrode on the bottom surface of the piezoelectric layer. At least one of each of the first and the second resonators' electrodes is electrically connected to the acoustic wave filter element. The first resonator has a first notch in resonator impedance at a first frequency. The second resonator includes a first mass loading layer on the second resonator electrode such that the second resonator has a second notch in resonator impedance at a second frequency different from the first frequency.

Acoustic wave devices and interdigital transducer (IDT) arrangements for surface acoustic wave (SAW) devices are disclosed. Representative SAW devices are described herein that provide sharp transitions between passband frequencies and frequencies that are outside of desired passbands. A SAW device may include several IDTs arranged between reflective structures on a piezoelectric material and one or more additional IDTs or electrode pairs that are configured to modify the influence of parasitic capacitance, or other internal device capacitance, thereby improving steepness on the upper side of a passband as well as improving rejection for frequencies outside of the passband. The one or more additional IDTs or electrode pairs may be configured as at least one of a capacitor, an IDT capacitor, an IDT with a floating electrode, or combinations thereof.

An acoustic wave device includes a piezoelectric substrate including a support including a support substrate and a piezoelectric layer on the support and including first and second main surfaces, a functional electrode on the first or second main surface and including a pair of electrodes, a first support on the piezoelectric substrate and surrounding the functional electrode, at least one second support on the piezoelectric substrate in a portion surrounded by the first support, and a lid on the first and second supports. The second support does not overlap an intersecting region when viewed from an electrode extending direction and from an electrode facing direction.

Techniques are disclosed for forming high frequency film bulk acoustic resonator (FBAR) devices that include a bottom electrode formed of a two-dimensional electron gas (2DEG). The disclosed FBAR devices may be implemented with various group III-nitride (III-N) materials, and in some cases, the 2DEG may be formed at a heterojunction of two epitaxial layers each formed of III-N materials, such as a gallium nitride (GaN) layer and an aluminum nitride (AlN) layer. The 2DEG bottom electrode may be able to achieve similar or increased carrier transport as compared to an FBAR device having a bottom electrode formed of metal. Additionally, in some embodiments where AlN is used as the piezoelectric material for the FBAR device, the AlN may be epitaxially grown which may provide increased performance as compared to piezoelectric material that is deposited by traditional sputtering techniques.

Embodiments of the invention include a waveguide structure that includes a first piezoelectric transducer that is positioned in proximity to a first end of a cavity of an organic substrate. The first piezoelectric transducer receives an input electrical signal and generates an acoustic wave to be transmitted with a transmission medium. A second piezoelectric transducer is positioned in proximity to a second end of the cavity. The second piezoelectric transducer receives the acoustic wave from the transmission medium and generates an output electrical signal.

Acoustic wave devices and interdigital transducer (IDT) arrangements for surface acoustic wave (SAW) devices are disclosed. Representative SAW devices are described herein that provide sharp transitions between passband frequencies and frequencies that are outside of desired passbands. A SAW device may include several IDTs arranged between reflective structures on a piezoelectric material and one or more additional IDTs or electrode pairs that are configured to modify the influence of parasitic capacitance, or other internal device capacitance, thereby improving steepness on the upper side of a passband as well as improving rejection for frequencies outside of the passband. The one or more additional IDTs or electrode pairs may be configured as at least one of a capacitor, an IDT capacitor, an IDT with a floating electrode, or combinations thereof.

The present disclosure relates to filter circuitry, which includes a first node and a second node, a series resonator coupled between the first node and the second node, and a compensation circuit coupled in parallel with the series resonator and located between the first node and the second node. Herein, the compensation circuit includes a tunable acoustic resonator with at least one transduction structure. The at least one transduction structure includes at least one ferroelectric material, and polarization of the at least one ferroelectric material varies with an electric field across the at least one ferroelectric material. Upon adjusting a direct current voltage applied to the tunable acoustic resonator, the compensation circuit is capable of providing a variable negative equivalent capacitance to at least partially cancel out an equivalent capacitance presented by the series resonator between the first node and the second node.