摘要:
A filter using an air gap type film bulk acoustic resonator is provided. The present filter includes a substrate on which a first port, a second port, and a ground port are formed to be connected to an external terminal; at least one first film bulk acoustic resonator serially connecting the first port to the second port on the substrate; at least one second film bulk acoustic resonator parallel connected to an interconnection node formed between the first port and the second port; and at least one inductor serially connecting the second film bulk acoustic resonator to the ground port. The inductor included in the filter is fabricated with the first and second film bulk acoustic resonators as one body. Accordingly, a small-sized filter may be fabricated through a simplified process.
摘要:
A film bulk acoustic resonator (FBAR) has a support structure, a piezoelectric resonator, and a signal line that is electrically connected, e.g., through a via, to the piezoelectric resonator, all on a semiconductor substrate. Support(s) and/or the via mount the piezoelectric resonator at a predetermined distance from the semiconductor substrate, allowing an ideal shape of the resonator to be realized. The signal line may include a patterned inductor. A capacitor can be formed between the via and the signal line. The resonance characteristics can be enhanced since the substrate loss caused by the driving of the resonator can be prevented due to an air gap formed by the predetermined distance. The resonance frequency can be adjusted by altering the pattern of the inductor, the capacitance of the capacitor and/or the thickness of the piezoelectric layer, also allowing Impedance matching to be readily realized.
摘要:
A film bulk acoustic resonator includes a substrate (101); a lower electrode (110) formed on top of the substrate (101); a piezoelectric membrane (113) formed on top of the lower electrode (110) and having a crystallographic axis (CC) so inclined as to generate a total reflection when an acoustic wave advances toward the lower electrode (110); and an upper electrode (115) formed on top of the piezoelectric membrane (113). The circumference of the piezoelectric membrane (113) may comprise an enveloping wall (117) which may be patterned on the same layer as that of forming the upper electrode (115).
摘要:
An integrated filter including a film bulk acoustic resonator (FBAR) and a surface acoustic wave (SAW) resonator and a method of fabricating the integrated filter. The integrated filter includes: a substrate; a first electrode positioned in a predetermined first area on an upper surface of the substrate; a first piezoelectric layer positioned on the first electrode; a second electrode positioned on the first piezoelectric layer; a second piezoelectric layer positioned in a predetermined second area on the upper surface of the substrate; and at least one inter-digital transducer (IDT) electrode positioned on the second piezoelectric layer. The IDT electrode includes: a first IDT electrode formed in a comb structure on the second piezoelectric layer; and a second IDT electrode formed in a comb structure on the second piezoelectric layer so as to mesh with the first IDT electrode. The first and second piezoelectric layers are formed of an identical material. Thus, an integrated filter which operates in various frequency bands can be made compact.
摘要:
An air-gap type film bulk acoustic resonator (FBAR) is created by securing two substrate parts, one providing a resonance structure and the other providing a separation structure, i.e., a cavity. When the two substrate parts are secured, the resonance structure is over the cavity, forming an air gap isolating the resonant structure from the support substrate. The FBAR may be used to form a duplexer, which includes a plurality of resonance structures, a corresponding plurality of cavities, and an isolation part formed between the cavities. The separate creation of the resonance structures and the cavities both simplifies processing and allows additional elements to be readily integrated in the cavities.
摘要:
An air-gap type film bulk acoustic resonator (FBAR) is created by securing two substrate parts, one providing a resonance structure and the other providing a separation structure, i.e., a cavity. When the two substrate parts are secured, the resonance structure is over the cavity, forming an air gap isolating the resonant structure from the support substrate. The FBAR may be used to form a duplexer, which includes a plurality of resonance structures, a corresponding plurality of cavities, and an isolation part formed between the cavities. The separate creation of the resonance structures and the cavities both simplifies processing and allows additional elements to be readily integrated in the cavities.
摘要:
A filter using an air gap type film bulk acoustic resonator is provided. The present filter includes a substrate on which a first port, a second port, and a ground port are formed to be connected to an external terminal; at least one first film bulk acoustic resonator serially connecting the first port to the second port on the substrate; at least one second film bulk acoustic resonator parallel connected to an interconnection node formed between the first port and the second port; and at least one inductor serially connecting the second film bulk acoustic resonator to the ground port. The inductor included in the filter is fabricated with the first and second film bulk acoustic resonators as one body. Accordingly, a small-sized filter may be fabricated through a simplified process.
摘要:
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.