Provided are a piezoelectric device and a method of fabricating the same and the piezoelectric device may include a substrate including a 3-dimensional pattern surface layer; and a piezoelectric material layer, which is formed on the pattern surface layer and forms a 3-dimensional interface with the pattern surface layer.

A method and structure for a transfer process for an acoustic resonator device. In an example, a bulk acoustic wave resonator (BAWR) with an air reflection cavity is formed. A piezoelectric thin film is grown on a crystalline substrate. A first patterned electrode is deposited on the surface of the piezoelectric film. An etched sacrificial layer is deposited over the first electrode and a planarized support layer is deposited over the sacrificial layer, which is then bonded to a substrate wafer. The crystalline substrate is removed and a second patterned electrode is deposited over a second surface of the film. The sacrificial layer is etched to release the air reflection cavity. Also, a cavity can instead be etched into the support layer prior to bonding with the substrate wafer. Alternatively, a reflector structure can be deposited on the first electrode, replacing the cavity.

A piezoelectric thin film resonator includes: a substrate; a piezoelectric film located on the substrate, the piezoelectric film including an aluminum nitride film containing a II-group or XII-group element and a IV-group or V-group element, a concentration of the IV-group or V-group element being higher than a concentration of the II-group or XII-group element in a middle region in a thickness direction, the concentration of the II-group or XII-group element being higher than the concentration of the IV-group or V-group element in at least one of end regions in the thickness direction; and a lower electrode and an upper electrode facing each other across the piezoelectric film.

Using a chemical vapor-phase deposition (CVD), physical vapor phase deposition (PVD) process or similar, novel directionally-oriented piezoelectric materials are created from zinc oxide (ZnO) and similar materials with innovative features that enhance their performance as ultrasonic transducers. Applications for these enhanced piezoelectric materials and transducers include: underwater sonar devices, non-destructive testing devices, tank level indicators, eddy current detectors, ultrasonic wellfield characterization devices, and in-fluid imaging devices (e.g., under-water and under-sodium viewing devices).

An acoustic wave filter having thermal sensing acoustic wave resonator comprises a substrate, a plurality of series acoustic wave resonators formed on the substrate, at least one shunt acoustic wave resonator formed on the substrate and a thermal sensing acoustic wave resonator. The thermal sensing acoustic wave resonator is one of a series acoustic wave resonator and a shunt acoustic wave resonator. Thereby the thermal sensing acoustic wave resonator plays dual roles of thermal sensing and acoustic wave filtering.

A thermal sensor circuit comprises a conversion circuit which is one of a buck DC-DC converter circuit and a boost DC-DC converter circuit, wherein the conversion circuit comprises an inductor and an output terminal. A thermal sensor senses a thermal variation correlated to a capacitance variation of the thermal sensor. The capacitance variation induces an internal parasitic capacitance variation of the inductor which is connected in parallel to the thermal sensor and results a variation of an energy stored in the inductor. Hence a variation of a converted circuit signal outputting by the output terminal is caused, wherein the variation of the converted circuit signal is correlated to the thermal variation.

An integrated module of acoustic wave device with active thermal compensation comprises a substrate, an acoustic wave filter, an active adjustment circuit and at least one variable capacitance device. The acoustic wave filter comprises a plurality of series acoustic wave resonators formed on the substrate, at least one shunt acoustic wave resonator formed on the substrate and a thermal sensing acoustic wave resonator. Each of the variable capacitance device is connected in parallel to one of the series and shunt acoustic wave resonators. The active adjustment circuit outputs an active thermal compensation signal correlated to a thermal variation sensed by the thermal sensing acoustic wave resonator to the variable capacitance device. The active thermal compensation signal induces a capacitance variation of the variable capacitance device such that the impact of the thermal variation to the acoustic wave device is compensated.

A piezoelectric composite substrate for SAW devices with small loss is provided. A composite substrate for a surface acoustic wave device according to one embodiment of the present invention has a piezoelectric single crystal thin film, a support substrate, and a first intervening layer between the piezoelectric single crystal thin film and the support substrate. In the composite substrate, the first intervening layer is in contact with the piezoelectric single crystal thin film, and the acoustic velocity of the transverse wave in the first intervening layer is faster than the acoustic velocity of the fast transverse wave in the piezoelectric single crystal thin film.

An empty chamber component includes a pressure chamber formation substrate where a pressure chamber as an empty chamber is defined and a communication substrate bonded to the pressure chamber formation substrate. A piezoelectric element is provided on one side of the pressure chamber formation substrate. A flexible surface is located between the piezoelectric element and the pressure chamber. Empty portions are defined by the communication substrate closing recessed portions in the pressure chamber formation substrate. The empty portions are formed at positions where ends of the active section of the piezoelectric element pass through the empty portions in plan view.

An empty chamber component includes a pressure chamber formation substrate where a pressure chamber as an empty chamber is defined and a communication substrate bonded to the pressure chamber formation substrate. A piezoelectric element is provided on one side of the pressure chamber formation substrate. A flexible surface is located between the piezoelectric element and the pressure chamber. Empty portions are defined by the communication substrate closing recessed portions in the pressure chamber formation substrate. The empty portions are formed at positions where ends of the active section of the piezoelectric element pass through the empty portions in plan view.