Film bulk acoustic resonator and preparation method thereof

Abstract

The invention discloses a film bulk acoustic resonator and a preparation method thereof. The film bulk acoustic resonator comprises a substrate, a cavity and a piezoelectric stack structure, the piezoelectric stack structure sequentially comprises a bottom electrode, a piezoelectric material layer and a top electrode from bottom to top; the piezoelectric material layer is composed of a piezoelectric material effective area, a piezoelectric material outer area and an anchor. The effective area of the piezoelectric material is smaller than the cavity area. The edge of the effective area of the piezoelectric material contacts with air and is connected with the outer area of the piezoelectric material through an anchor. The effective area of the piezoelectric material is suspended above the cavity through the support of the anchor; during resonance, sound waves transversely propagating in the effective area of the piezoelectric material are reflected by air at the edge, in addition, duringresonance, only vibration of the working area of the piezoelectric stack structure is bound by anchors, the piezoelectric stack structure can vibrate more freely, stronger electric signals are generated while clutter influences are reduced, and therefore the performance of the film bulk acoustic resonator is improved.

Description

technical field [0001] The invention relates to the technical field of filter devices, in particular to a film bulk acoustic wave resonator and a preparation method thereof. Background technique [0002] The rapid development of wireless communication technology, especially the application of 5G communication technology makes the communication protocol more and more complicated, and the frequency band used is higher and higher, which puts forward the requirements of high integration, low power consumption and high performance for radio frequency devices. In the RF front-end module, the RF filter plays a vital role, especially in high-frequency communication, the filter based on the thin film bulk acoustic resonator technology plays an important role because of its excellent performance. Thin film bulk acoustic resonator has the characteristics of high resonance frequency, CMOS process compatibility, high quality factor, low loss, low temperature coefficient and high power ca...

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Problems solved by technology

However, this method only increases the reflection of the transversely propagating sound waves on the electrodes, and has little effect on the transversely propagating sound waves inside the piezoelectric material, and cannot effectively reduce the influence of the transversely propagating sound waves inside the piezoelectric material.

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