Abstract: A bulk acoustic wave (BAW) resonator is disclosed. The BAW resonator includes: a first electrode, a second electrode, a piezoelectric layer disposed between the first electrode and the second electrode, a substrate positioned adjacent to the second electrode, and an active area having at least one biarc boundary.

Abstract: Bulk acoustic wave (BAW) resonators, and electrical filters that incorporate the BAW resonators, are described. Generally, the BAW resonators comprise a substrate comprising an acoustic reflector; a first electrode disposed over the acoustic reflector; a piezoelectric layer disposed over the first electrode, the piezoelectric layer comprising scandium-doped aluminum nitride (ASN); a diffusion barrier layer disposed over the piezoelectric layer; and a second electrode disposed over the diffusion barrier layer. The diffusion barrier layer configured to prevent diffusion of material of the first electrode into the piezoelectric layer.

Abstract: A bulk acoustic wave (BAW) resonator is disclosed. The BAW resonator includes: a first electrode, a second electrode, a piezoelectric layer disposed between the first electrode and the second electrode, a substrate positioned adjacent to the second electrode, and an active area having at least one biarc boundary.

Abstract: A bulk acoustic wave (BAW) resonator is disclosed. The BAW resonator includes: a lower electrode; a piezoelectric layer disposed over the lower electrode; and an upper electrode over the piezoelectric layer. An opening having a first area exists in and extends completely through the upper electrode. The BAW resonator also includes a substrate disposed below the lower electrode; a cavity; and a pillar disposed in the cavity and extending to contact a portion of the lower electrode disposed beneath the opening. The pillar has a second area that is less than the first area. There are no electrical connections that extend across the opening from one side to another.

Abstract: A bulk acoustic wave (BAW) resonator is disclosed. The BAW resonator includes: a lower electrode; a piezoelectric layer disposed over the lower electrode; and an upper electrode over the piezoelectric layer. An opening having a first area exists in and extends completely through the upper electrode. The BAW resonator also includes a substrate disposed below the lower electrode; a cavity; and a pillar disposed in the cavity and extending to contact a portion of the lower electrode disposed beneath the opening. The pillar has a second area that is less than the first area. There are no electrical connections that extend across the opening from one side to another.

Abstract: Bulk acoustic wave (BAW) resonators, and electrical filters that incorporate the BAW resonators, are described. Generally, the BAW resonators comprise a substrate comprising an acoustic reflector; a first electrode disposed over the acoustic reflector; a piezoelectric layer disposed over the first electrode, the piezoelectric layer comprising scandium-doped aluminum nitride (ASN); a diffusion barrier layer disposed over the piezoelectric layer; and a second electrode disposed over the diffusion barrier layer. The diffusion barrier layer configured to prevent diffusion of material of the first electrode into the piezoelectric layer.

Abstract: A bulk acoustic wave (BAW) resonator includes: an acoustic reflector disposed in a substrate; a lower electrode disposed over the acoustic reflector; a piezoelectric layer disposed over the lower electrode; and an upper electrode disposed over the piezoelectric layer. A contacting overlap of the lower electrode, the piezoelectric layer and the upper electrode over the acoustic reflector comprising an active area of the BAW resonator. An opening exists in the upper electrode in a region of the BAW resonator susceptible to unacceptable overheating.

Abstract: A bulk acoustic wave (BAW) resonator includes: an acoustic reflector disposed in a substrate; a lower electrode disposed over the acoustic reflector; a piezoelectric layer disposed over the lower electrode; and an upper electrode disposed over the piezoelectric layer. A contacting overlap of the lower electrode, the piezoelectric layer and the upper electrode over the acoustic reflector comprising an active area of the BAW resonator. An opening exists in the upper electrode in a region of the BAW resonator susceptible to unacceptable overheating.

Abstract: A bulk acoustic wave (BAW) resonator includes: a plurality of acoustic reflectors disposed in a substrate; a lower electrode disposed over the plurality of acoustic reflectors; a piezoelectric layer disposed over the lower electrode; and a plurality of upper electrodes, disposed over the piezoelectric layer. One of the plurality of upper electrodes is formed over a respective one of the plurality of acoustic reflectors. Each of the plurality of upper electrodes, the piezoelectric layer, the lower electrode, and each of the acoustic reflectors form an individual active area.

Abstract: A bulk acoustic wave (BAW) resonator includes: an acoustic reflector disposed in a substrate; a lower electrode disposed over the acoustic reflector; a piezoelectric layer disposed over the lower electrode; and an upper electrode disposed over the piezoelectric layer. A contacting overlap of the lower electrode, the piezoelectric layer and the upper electrode over the acoustic reflector comprising an active area of the BAW resonator. An opening exists in the upper electrode in a region of the BAW resonator susceptible to unacceptable overheating.

Abstract: A bulk acoustic wave (BAW) resonator includes: a plurality of acoustic reflectors disposed in a substrate; a lower electrode disposed over the plurality of acoustic reflectors; a piezoelectric layer disposed over the lower electrode; and a plurality of upper electrodes, disposed over the piezoelectric layer. One of the plurality of upper electrodes is formed over a respective one of the plurality of acoustic reflectors. Each of the plurality of upper electrodes, the piezoelectric layer, the lower electrode, and each of the acoustic reflectors form an individual active area.

Abstract: An film bulk acoustic wave resonator (FBAR) structure has an FBAR and a via disposed substantially directly beneath the FBAR. The via is in thermal contact with the FBAR. A plurality of vias may be included. The via(s) serve to dissipate heat generated by the FBAR structure during operation.

Abstract: An acoustic resonator device includes a temperature compensation structure disposed beneath the first electrode and above the substrate.

Abstract: An film bulk acoustic wave resonator (FBAR) structure has an FBAR and a via disposed substantially directly beneath the FBAR. The via is in thermal contact with the FBAR. A plurality of vias may be included. The via(s) serve to dissipate heat generated by the FBAR structure during operation.

Abstract: Acoustic resonator comprising an electret, and method of producing said resonator, application to switchable coupled resonator filters. The resonator comprises: at least one piezoelectric layer (30); electrodes (24, 26) on either side of this layer; and at least one electret layer (32) between the electrodes, to apply a permanent electric field to the piezoelectric layer. The intensity of this electric field is determined to shift the resonance frequency of the resonator by a desired value. The piezoelectric layer may contain electrical charges to itself constitute the electret layer.

Abstract: Acoustic resonator comprising an electret, and method of producing said resonator, application to switchable coupled resonator filters. The resonator comprises: at least one piezoelectric layer (30); electrodes (24, 26) on either side of this layer; and at least one electret layer (32) between the electrodes, to apply a permanent electric field to the piezoelectric layer. The intensity of this electric field is determined to shift the resonance frequency of the resonator by a desired value. The piezoelectric layer may contain electrical charges to itself constitute the electret layer.