1136 results about "Bulk acoustic wave" patented technology

A component working with acoustic bulk waves is provided that has a multi-layer substrate, where the multi-layer substrate comprises an integrated matching network and further circuit elements for adapting the electrical filter properties and can serve as carrier substrate for thin-film resonators.

A component that functions with bulk acoustic waves, particularly a bandpass filter, has an increased number of degrees of design freedom in order to improve the transmission characteristics of the component. The component has BAW resonators coupled acoustically in the vertical and / or lateral direction through common electrodes, coupling layer systems and through the excitation of lateral acoustic modes. Through the acoustic coupling of the resonators, it is possible to create additional pole points in the transfer function so that in this manner, the rejection band characteristics of a bandpass filter can be improved. Through acoustic paths which are added in addition to the electrical connection, the insertion loss can be reduced. Through an acoustic coupling instead of an electrical connection, decoupling between input and output loops of a circuit can be achieved.

A component operating with bulk acoustic waves has two Bulk Acoustic Wave (BAW) resonators that are stacked and are acoustically coupled to one another, with a first resonator being connected to an asymmetric port, and a second resonator being connected to a symmetrical port. The acoustic coupling is provided by a partially permeable coupling layer system, which has an alternating sequence of at least two λ / 4 mirror layers with different acoustic impedance. The coupling layer system furthermore has a compensation layer, which has an approximate thickness of λ / 8. The compensation layer according to the invention makes it possible to match any discrepancy in the phase difference (which is caused by reflections on the mirror layers) from the predetermined 180° between the connections of the symmetrical port to approximately 180°.

The invention discloses a thin film bulk acoustic wave resonator which comprises a substrate, a buffer layer, a piezoelectric layer and electrodes, and is characterized in that 1. A smooth concave groove and the buffer layer are arranged on the upper end surface of the substrate; the buffer layer crosses the concave groove and forms an air gap provided with a smooth upper convex edge with the substrate, and completely covers the air gap; the height of the lower top surface of the air gap is less than that of the substrate, and the air gap has flat surface and even change edge; 2. The edge of the buffer layer, which is contacted with the air gap and is close to the substrate is in smooth and outer-convex shape; the piezoelectric layer is arranged on the buffer layer; the electrodes include a bottom electrode and a top electrode; the bottom electrode is arranged in the piezoelectric layer on the buffer layer; the top electrode is arranged on the piezoelectric layer. The thin film bulk acoustic wave resonator has ingenious structure; a FBAR with stable structure and low loss can be fabricated on the substrate through the method, and the CMP process is avoided, so the thin film bulk acoustic wave resonator can be integrated into a CMOS chip conveniently.

A bulk GaN layer is on a first surface of a substrate, wherein the bulk GaN layer has a GaN transistor region and a bulk acoustic wave (BAW) device region. A source / drain layer is over a first surface of the bulk GaN layer in the GaN transistor region. A gate electrode is formed over the source / drain layer. A first BAW electrode is formed over the first surface of the bulk GaN layer in the BAW device region. An opening is formed in a second surface of the substrate, opposite the first surface of the substrate, which extends through the substrate and exposes a second surface of the bulk GaN layer, opposite the first surface of the bulk GaN layer. A second BAW electrode is formed within the opening over the second surface of the bulk GaN layer.

The invention relates to a laterally coupled bulk acoustic wave (LBAW) filter comprising a vibration layer for carrying bulk acoustic waves, electrode means comprising a first electrode coupled to the vibration layer for exciting to the vibration layer at least one longitudinal wave mode having a first frequency band and one shear wave mode having a second frequency band, and a second electrode coupled to the vibration layer for sensing the filter pass signal, the first and second electrodes being laterally arranged with respect to each other, and an acoustic reflector structure in acoustic connection with the vibration layer. According to the invention, the reflector structure is adapted to acoustically isolate the vibration layer from its surroundings at the first frequency band more efficiently than at the second frequency band for suppressing the effect of the shear wave mode at the second frequency band from the filter pass signal. The invention helps to improve the quality of LBAW filter passbands.

A method for fabricating a bulk acoustic wave (BAW) device comprising providing a growth substrate and growing an Group-III nitride epitaxial layer on the growth substrate. A first electrode is deposited on the epitaxial layer. A carrier substrate is provided and the growth substrate, epitaxial layer and first electrode combination is flip-chip mounted on the carrier substrate. The growth substrate is removed and a second electrode is deposited on the epitaxial layer with the epitaxial layer sandwiched between the first and second electrodes. A bulk acoustic wave (BAW) device comprises first and second metal electrodes and a Group-III nitride epitaxial layer sandwiched between the first and second electrodes. A carrier substrate is included, with the first and second electrodes and epitaxial layer on the carrier substrate.

A method for fabricating a bulk acoustic wave (BAW) device comprising providing a growth substrate and growing an Group-III nitride epitaxial layer on the growth substrate. A first electrode is deposited on the epitaxial layer. A carrier substrate is provided and the growth substrate, epitaxial layer and first electrode combination is flip-chip mounted on the carrier substrate. The growth substrate is removed and a second electrode is deposited on the epitaxial layer with the epitaxial layer sandwiched between the first and second electrodes. A bulk acoustic wave (BAW) device comprises first and second metal electrodes and a Group-III nitride epitaxial layer sandwiched between the first and second electrodes. A carrier substrate is included, with the first and second electrodes and epitaxial layer on the carrier substrate.

A tuning circuit for adjusting an oscillation frequency of an oscillator circuit. The tuning circuit comprises a film bulk acoustic wave resonator (FBAR) having a series resonance frequency and a parallel resonance frequency, and an inductor coupled in series or parallel with the film bulk acoustic wave resonator. The series connection of the inductor and FBAR decreases the series resonance frequency. The parallel connection of the inductor and the FBAR increases the parallel resonance frequency. The tuning circuit further comprises a varactor coupled in series or parallel with the inductor and the FBAR combination. The varactor tunes the oscillation frequency over the increased tuning range.

A method for fabricating bulk acoustic wave resonator with mass adjustment structure, comprising following steps of: forming a sacrificial structure mesa on a substrate; etching the sacrificial structure mesa such that any two adjacent parts have different heights, a top surface of a highest part of the sacrificial structure mesa is coincident with a mesa top extending plane; forming an insulating layer on the sacrificial structure mesa and the substrate; polishing the insulating layer to form a polished surface; forming a bulk acoustic wave resonance structure including a top electrode, a piezoelectric layer and a bottom electrode on the polished surface; etching the sacrificial structure mesa to form a cavity; the insulating layer between the polished surface and the mesa top extending plane forms a frequency tuning structure, the insulating layer between the mesa top extending plane and the cavity forms a mass adjustment structure.

A bulk acoustic wave (BAW) resonator structure comprises a first electrode disposed over a substrate, a first piezoelectric layer disposed over the first electrode, a second electrode disposed over the first piezoelectric layer, and a collar structure disposed around a perimeter of an active region defined by an overlap between the first electrode, the second electrode, and the piezoelectric layer.

A thin-film bulk acoustic wave (BAW) resonator, such as SBAR or FBAR, for use in RF selectivity filters operating at frequencies of the order of 1 GHz. The BAW resonator comprises a piezoelectric layer (14) having first and second surfaces on opposing sides, a first electrode (16) extending over the first surface, and a second electrode (12) extending over the second surface, the extent of the area of overlap (R1) of the first and second electrodes determining the region of excitation of the fundamental thickness extensional (TE) mode of the resonator. The insertion loss to the resonator is reduced by providing a dielectric material (18) in the same layer as the first electrode (16) and surrounding that electrode. The material constituting the dielectric material (18) has a different mass, typically between 5% and 15%, from the material comprising the first electrode (16) it surrounds. The mass of the dielectric material (18) can be lower or higher than the mass of the first electrode (16). Planarisation of the dielectric material (18) enhances the performance of the device.

Disclosed herein is an FBAR (film bulk acoustic wave resonator) device and a manufacturing method thereof. The FBAR device comprises a substrate, a resonance unit including a lower electrode, a piezoelectric film, and an upper electrode, which are successively stacked on the substrate, and a passivation layer formed substantially throughout an upper surface and peripheral surface of the resonance unit in order to protect the resonance unit. A partial region of the passivation layer formed on at least the upper electrode has a thickness required to compensate for a difference between a resonant frequency of the resonance unit and a desired target resonant frequency.

A resonator having a membrane formed of a piezoelectric layer sandwiched between first and second electrode is suspended above a cavity formed from the back surface of the support structure. In one embodiment, the cavity walls are substantially perpendicular to the back surface. In another embodiment, the first electrode is formed in the cavity such that it is electrically connected to an electrode on the back surface of the support structure. In yet another embodiment, the cavity is formed via an etch through via holes in the back surface of the support structure, which leads to greater flexibility in designing a method of manufacture while reducing the need for alignment relative to other designs.