A thin-film bulk acoustic wave resonator and its preparation method

Abstract

The invention discloses a thin-film bulk acoustic wave resonator and a preparation method thereof, comprising a base, a cavity and a piezoelectric stack structure; the piezoelectric stack structure is sequentially bottom electrode, piezoelectric material layer and top electrode from bottom to top; The material layer is composed of an effective area of ​​the piezoelectric material, an outer area of ​​the piezoelectric material and an anchor; the effective area of ​​the piezoelectric material is smaller than the area of ​​the cavity. The edge of the active area of ​​the piezoelectric material is in contact with the air, and is connected to 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. The sound wave propagating laterally inside the effective area of ​​the piezoelectric material is reflected by the air at the edge during resonance. In addition, only the anchor restrains the vibration of the working area of ​​the piezoelectric stack structure during resonance. The electrical stack structure can vibrate more freely, reduce the influence of clutter and generate stronger electrical signals, thereby improving the performance of the film bulk acoustic resonator.

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...

AI Technical Summary

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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