Techniques for improving Bulk Acoustic Wave (BAW) resonator structures are disclosed, including filters, oscillators and systems that may include such devices. A first layer of doped piezoelectric layer material and a second layer of piezoelectric material may be acoustically coupled with one another to have a piezoelectrically excitable resonance mode. The first layer of doped piezoelectric material may have a first piezoelectric axis orientation, and the second layer of piezoelectric material may have a second piezoelectric axis orientation that substantially opposes the first piezoelectric axis orientation of the first layer of piezoelectric material. An acoustic reflector including a first pair of metal electrode layers may be electrically and acoustically coupled with the first layer of doped piezoelectric material and the second layer of piezoelectric material to excite the piezoelectrically excitable main resonance mode at a resonant frequency.

Techniques for improving acoustic wave device structures are disclosed, including filters and systems that may include such devices. An acoustic wave device may include a substrate. The acoustic wave device may include first and second layers of piezoelectric material acoustically coupled with one another, in which the first layer of piezoelectric material has a first piezoelectric axis orientation, and the second layer of piezoelectric material has a second piezoelectric axis orientation that substantially opposes the first piezoelectric axis orientation of the first layer of piezoelectric material. The acoustic wave device may include an interposer layer interposed between the first and second layers of piezoelectric material. The interposer may facilitate an enhancement of an electromechanical coupling coefficient of the acoustic wave device.

Techniques for improving Bulk Acoustic Wave (BAW) reflector and resonator structures are disclosed, including filters, oscillators and systems that may include such devices. First and second layers of piezoelectric material may be acoustically coupled with one another to have a piezoelectrically excitable resonance mode. The first layer of piezoelectric material may have a first piezoelectric axis orientation, and the second layer of piezoelectric material may have a second piezoelectric axis orientation that substantially opposes the first piezoelectric axis orientation of the first layer of piezoelectric material. A top acoustic reflector electrode may include a first pair of top metal electrode layers electrically and acoustically coupled with the first and second layer of piezoelectric material to excite the piezoelectrically excitable resonance mode at a resonant frequency of the BAW resonator. The resonant frequency of the BAW resonator may be in a super high frequency band or an extremely high frequency band.

A method for manufacturing a piezoelectric vibration element that includes preparing a piezoelectric substrate; providing a first electrode layer on a first main surface of the piezoelectric substrate; arranging a mask on a side of the first main surface of the piezoelectric substrate, the mask including a center region and a peripheral region located along a periphery of the center region; and irradiating a radiation beam through the mask toward the first main surface of the piezoelectric substrate such that a larger amount of the radiation beam passes through the peripheral region than the center region of the mask so as to remove a part of the first electrode layer to form a first excitation electrode that decreases in thickness from the center region to the peripheral region of the mask on the first main surface of the piezoelectric substrate.

An object is to provide a frequency adjustment method for a piezoelectric resonator device that is applicable to a microminiaturized device and that can adjust the frequency without deteriorating the accuracy of frequency adjustment. A frequency adjustment method for a tuning-fork quartz resonator is applicable to a tuning-fork quartz resonator that includes a tuning-fork quartz resonator piece having a pair of resonator arms 31, 32 and metallic adjustment films W formed on the resonator arms. The frequency adjustment method adjusts the frequency by reduction of a mass of the metallic adjustment films W. The frequency adjustment method includes: a rough adjustment step for roughly adjusting the frequency by partially thinning or removing the metallic adjustment films W; and a fine adjustment step for finely adjusting the frequency by at least partially thinning or removing products W1, W2 derived from the metallic adjustment film W during the rough adjustment step.

This application provides a monolithic integrated BAW resonator production method, including: preparing an imprint template; forming a mask material layer on a substrate; pressing the mask material layer by using the imprint template in a direction of the substrate, to form a mask groove; performing plasma etching on the substrate by using the mask material layer, as a mask, that is used to form the mask groove, to form, on the substrate, grooves that one-to-one correspond to positions of several mask grooves; and forming, in the several grooves, bottom electrode layers, piezoelectric layers, and top electrode layers that are sequentially stacked, to form resonators of different frequencies.

Techniques for improving Bulk Acoustic Wave (BAW) resonator structures are disclosed, including fluidic systems, oscillators and systems that may include such devices. A bulk acoustic wave (BAW) resonator may comprise a substrate and a first layer of piezoelectric material. The bulk acoustic wave (BAW) resonator may comprise a top electrode. A sensing region may be acoustically coupled with the top electrode of the bulk acoustic wave (BAW) resonator.

The vibrator element includes a base part, a vibrating arm extending from the base part, and a weight provided to the vibrating arm, wherein the weight includes a thick film part, a thin film part thinner in film thickness than the thick film part, and a connection part which is located between the thick film part and the thin film part to connect the thick film part and the thin film part to each other, and which forms a taper shape gradually decreasing in film thickness in a direction from the thick film part side toward the thin film part.

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.