581 results about "Thin-film bulk acoustic resonator" patented technology

A pit (52) is formed in a substrate comprising a silicon wafer (51) on a surface of which a silicon oxide thin layer (53) is formed. A sandwich structure (60) comprising a piezoelectric layer (62) and lower and upper electrodes (61, 63) joined to both surfaces of the piezoelectric layer is disposed so as to stride over the pit (52). The upper surface of the lower electrode (61) and the lower surface of the piezoelectric layer (62) joined to the upper surface of the lower electrode are treated so that the RMS variation of the height thereof is equal to 25 nm or less. The thickness of the lower electrode (61) is set to 150 nm or less. According to such a structure, there is provided a high-performance thin film bulk acoustic resonator which are excellent in electromechanical coupling coefficient and acoustic quality factor.

The film acoustically-coupled transformer (FACT) has a first and second decoupled stacked bulk acoustic resonators (DSBARs). Each DSBAR has a lower film bulk acoustic resonator (FBAR), an upper FBAR atop the lower FBAR, and an acoustic decoupler between them FBARs. Each FBAR has opposed planar electrodes and a piezoelectric element between the electrodes. A first electrical circuit interconnects the lowers FBAR of the first DSBAR and the second DSBAR. A second electrical circuit interconnects the upper FBARs of the first DSBAR and the second DSBAR. In at least one of the DSBARs, the acoustic decoupler and one electrode of the each of the lower FBAR and the upper FBAR adjacent the acoustic decoupler constitute a parasitic capacitor. The FACT additionally has an inductor electrically connected in parallel with the parasitic capacitor. The inductor increases the common-mode rejection ratio of the FACT.

A thin film bulk acoustic resonator includes a piezoelectric film, and a pair of electrodes between which the piezoelectric film is interposed. The piezoelectric film includes an outer region extending outwards from at least a portion of the periphery of a resonator portion composed of the pair of electrodes and the piezoelectric film. The outer region includes, in at least a portion thereof, an acoustic damping region for damping acoustic waves.

A band-pass filter has a ladder-type circuit including first and second terminals whose characteristic impedances are Z0, and series elements and shunt elements disposed between a first terminal and a second terminal, each of the series elements and shunt elements containing a film bulk acoustic resonator. Assuming that characteristic impedance of any one of the series elements is Z1 and that characteristic impedance of any one of the shunt elements is Z2, the characteristic impedances Z0, Z1, and Z2 have a relation of 1<(Z1/Z0)<2, preferably 1.3<(Z1/Z0)<1.7, and 0.5<(Z2/Z0)<1, preferably 0.6<(Z2/Z0)<0.8.

Disclosed are a film bulk acoustic resonator (FBAR) device and a method for fabricating the film bulk acoustic resonator (FBAR) device. The film bulk acoustic resonator (FBAR) device comprises a membrane layer having a plurality of active regions and provides different resonant frequencies by providing different thicknesses of the active regions of series resonators and shunt resonators, and by controlling the thicknesses, respectively. A plurality of the film bulk acoustic resonator (FBAR) devices having different resonant frequencies are manufactured on a substrate, thereby simultaneously manufacturing a transmission filter and a reception filter on the same substrate. Further, the film bulk acoustic resonator (FBAR) device has a stable structure and excellent characteristics.

A method for fabricating a film bulk acoustic resonator (FBAR) includes depositing a dielectric layer on a substrate, providing a sacrificial layer on part of the dielectric layer; providing a bottom electrode on part of the sacrificial layer on part of the dielectric layer; providing a piezoelectric layer on the bottom electrode; patterning a top electrode on the piezoelectric layer; and removing the sacrificial layer. The substrate may have a cavity receiving the sacrificial layer. As a result, a cantilevered resonator having an air gap between the bottom electrode and the dielectric layer may be simply fabricated.

A duplexer includes: first and second filters including film bulk acoustic resonators (FBARs) arranged in a ladder form; first and second integrated-passive devices (IPDs) provided between a common terminal and the first and second filters; and a substrate on which the first and second filters and the first and second IPDs are mounted. The substrate includes conductive patterns that realize inductances connected between the first and second filters and ground. The first and second IPDs includes inductors connected to the first and second filters.

A film bulk acoustic resonator includes: a substrate having; a lower electrode extending; a piezoelectric film provided on the lower electrode; an upper electrode opposed to the lower electrode and provided on the piezoelectric film; and a plurality of protrusions. The substrate has a cavity in a surface thereof. The lower electrode extends above the cavity from an upper surface of the substrate. The protrusions are provided below the lower electrode in the cavity.

A thin film bulk acoustic resonator is provided in which the spurious caused by a lateral vibration mode is reduced.

The thin film bulk acoustic resonator includes a laminated body having a first electrode 12, a piezoelectric layer 13 adjacently formed on an upper surface of the first electrode 12, and a second electrode 14 adjacently formed on an upper surface of the piezoelectric layer 13, and is made such that these first and second electrodes 12 and 14 have boundary surfaces contacting with air, in which the whole end surface of the piezoelectric layer 13 is made to exist inside the first electrode 12 and second electrode 14.

The film bulk acoustic wave resonator includes a laminate structure composed of a piezoelectric layer, and first and second electrode layers interposing at least part of the piezoelectric layer, in which the first metal electrode is dispersively formed on an electrode plane facing the second metal electrode, and a gap is formed in a substrate correspondingly to the laminate-structured resonance part. Except for an area of a wire electrode electrically connected to the first electrode layer and an area of a wire electrode electrically connected to the second electrode layer, the piezoelectric layer, first electrode layer and second electrode layer do not come in contact with the insulating substrate but are supported on a hollow. Also, a prop is formed in the gap to support the laminate structure.

A tuneable film bulk acoustic resonator (FBAR) device. The FBAR device includes a bottom electrode, a top electrode and a piezoelectric layer in between the bottom electrode and the top electrode. The piezoelectric layer has a first overlap with the bottom electrode, where the first overlap is defined by a projection of the piezoelectric layer onto the bottom electrode in a direction substantially perpendicular to a plane of the bottom electrode. The FBAR device also includes a first dielectric layer in between the piezoelectric layer and the bottom electrode and a mechanism for reversibly varying an internal impedance of the device, so as to tune a resonant frequency of the FBAR device.