A resonator structure (FBAR) made of electrodes sandwich a piezoelectric material. The intersection of the two conducting electrodes defines the active area of the acoustic resonator. The active area is divided into two concentric areas; a perimeter or frame, and a central region. An annulus is added to one of the two conducting electrodes to improve the electrical performance (in terms of Q).

Thin film bulk acoustic resonator with a mass loaded perimeter

Disclosed is an acoustic resonator that includes a substrate, a first electrode, a layer of piezoelectric material, a second electrode, and an alternating frame region. The first electrode is adjacent the substrate, and the first electrode has an outer perimeter. The piezoelectric layer is adjacent the first electrode. The second electrode is adjacent the piezoelectric layer and the second electrode has an outer perimeter. The alternating frame region is on one of the first and second electrodes.

Acoustic resonator performance enhancement using alternating frame structure

Film bulk acoustic resonators (FBARs) stacked FBARs (SBARS) including at least two curved edges are disclosed.

Piezoelectric resonator structures and electrical filters

Film bulk acoustic resonators (FBARs) having frame elements and filters including the resonators are described.

Piezoelectric resonator structures and electrical filters having frame elements

An acoustic resonator comprises a first electrode a second electrode and a piezoelectric layer disposed between the first and second electrodes. The acoustic resonator further comprises a reflective element disposed beneath the first electrode, the second electrode and the piezoelectric layer. An overlap of the reflective element, the first electrode, the second electrode and the piezoelectric layer comprises an active area of the acoustic resonator. The acoustic resonator also comprises a bridge adjacent to a termination of the active area of the acoustic resonator.

Acoustic resonator structure comprising a bridge

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.

Thin film acoustic resonator and method of producing the same

A transmission band filter (110) having a series of elements (111, 113, 115) each composed of a film bulk acoustic resonator and grounded shunt elements (112, 114) is connected between a transmission port (102) and an antenna port (106). A reception band filter (130) having a series of elements (131, 133, 135) each composed of a film bulk acoustic resonator and grounded shunt elements (132, 134, 136) is connected between a reception port (104) and the antenna port (106). A film bulk acoustic resonator (150) for adjustment is connected between the antenna port (106) and the ground. The resonance frequency of the adjusting film bulk acoustic resonator (150) lies between the upper limit frequency of the transmission frequency pass band of the transmission band filter (110) and the lower limit frequency of the reception frequency pass band of the reception band filter (130). Therefore a transmission/reception switch such that the switch can be a monolithic element, the breakdown power is good, the size is small, and the cost is low is provided.

Chisen Hashimoto

Papers

Thin film acoustic resonator and method of producing the same

Filter using film bulk acoustic resonator and transmission/reception switch