An RF integrated circuit device can includes a substrate and a High Electron Mobility Transistor (HEMT) device on the substrate including a ScAlN layer configured to provide a buffer layer of the HEMT device to confine formation of a 2DEG channel region of the HEMT device. An RF piezoelectric resonator device can be on the substrate including the ScAlN layer sandwiched between a top electrode and a bottom electrode of the RF piezoelectric resonator device to provide a piezoelectric resonator for the RF piezoelectric resonator device.

The present disclosure provides a piezoelectric resonator comprising a substrate having an acoustic reflection mirror, a bottom electrode stacked on the substrate, a piezoelectric layer disposed on the substrate and covering the bottom electrode, and a top electrode stacked on a surface of piezoelectric layer distal to the bottom electrode. An overlapping portion of the acoustic reflection mirror, the bottom electrode, the piezoelectric layer, and the top electrode along a thickness direction of the piezoelectric resonator is a resonance region. A sidewall of the top electrode or a bottom electrode recesses to form a recessing portion. The recessing portion does not extend to an upper surface or a lower surface of the top electrode or the bottom electrode.

A system for a wireless communication infrastructure using single crystal devices. The wireless system can include a controller coupled to a power source, a signal processing module, and a plurality of transceiver modules. Each of the transceiver modules includes a transmit module configured on a transmit path and a receive module configured on a receive path. The transmit modules each include at least a transmit filter having one or more filter devices, while the receive modules each include at least a receive filter. Each of these filter devices includes a single crystal acoustic resonator device formed with a thin film transfer process with at least a first electrode material, a single crystal material, and a second electrode material. Wireless infrastructures using the present single crystal technology perform better in high power density applications, enable higher out of band rejection (OOBR), and achieve higher linearity as well.

An acoustic wave device includes: a piezoelectric substrate; electrodes sandwiching the piezoelectric substrate and exciting a thickness shear vibration in the piezoelectric substrate; and an edge region that is a region surrounding a center region of a resonance region, wherein a first region of the edge region is located on both sides of the center region in a first direction substantially parallel to a displacement direction of a thickness shear vibration, a second region of the edge region is located on both sides of the center region in a second direction substantially perpendicular to the first direction, a width of the second region is different from a width of the first region, and acoustic velocities of acoustic waves in the piezoelectric substrate in the first and second regions are less than that in the piezoelectric substrate in the center region.

Disclosed is an air-gap type film bulk acoustic resonator (FBAR) including a substrate including an air-gap portion with a top surface in which a substrate cavity is formed, a lower electrode formed above the substrate while surrounding the air-gap portion, a piezoelectric layer formed above the lower electrode, and an upper electrode formed above the piezoelectric layer corresponding to a virtual area formed according to a vertical projection of the air-gap portion. Here, the piezoelectric layer includes a void portion having a piezoelectric cavity between the lower electrode and the upper electrode, and the void portion is formed below an edge portion corresponding to an end part of the upper electrode.

Embodiments of this disclosure relate to bulk acoustic wave resonators on a substrate. The bulk acoustic wave resonators include a first bulk acoustic wave resonator, a second bulk acoustic wave resonator, a conductor electrically connecting the first bulk acoustic wave resonator to the second bulk acoustic wave resonator, and an air gap positioned between the conductor and a surface of the substrate.

A film bulk acoustic wave resonator comprising a piezoelectric film having a central region defining a main active domain in which a main acoustic wave is generated during operation, an upper electrode disposed on a top surface of the piezoelectric film, a lower electrode disposed on a lower surface of the piezoelectric film, a dielectric material layer disposed on a lower surface of the lower electrode, and lower recessed frame regions disposed laterally on opposite sides of the central region, the lower recessed frame regions defined by regions of one of the dielectric material or of the lower electrode having a lesser thickness than the thickness of the one of the dielectric material layer or of the lower electrode in the central region.

Aspects of this disclosure relate to bulk acoustic wave devices that have a piezoelectric layer between a first electrode and a second electrode and a suspended frame structure that is suspended over a gap. The gap can be between the first electrode and the piezoelectric layer or between the second electrode and the piezoelectric layer. The bulk acoustic wave devices can have an inner raised frame portion inside of the suspended frame. The gap can be disposed between portions of the first and second electrodes that extend past an end of the piezoelectric layer. A conductive material can extend through an opening in a passivation layer at a location directly above the gap.

A bulk acoustic wave (BAW) device is provided comprising a first electrode, a second electrode, a piezoelectric layer positioned between the first electrode and the second electrode, and a raised frame structure outside of a middle area of an active domain of the BAW device, the raised frame structure comprising one or more raised frame layer(s). At least one of the raised frame layer(s) comprises a tapered portion tapering in a direction towards the middle area of the active domain. A packaged module comprising such a BAW device is also provided. A wireless mobile device comprising such a packaged module is 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 including a first layer and a second layer. A material of the first layer is different from the material of the second layer.