Bulk acoustic wave resonator and bulk acoustic wave filter

Abstract

The invention provides a bulk acoustic wave resonator and a bulk acoustic wave filter, and relates to the technical field of filters. The bulk acoustic wave resonator comprises a substrate, an acoustic reflection structure, a bottom electrode, a piezoelectric layer and a top electrode, wherein the acoustic reflection structure, the bottom electrode, the piezoelectric layer and the acoustic reflection structure are sequentially stacked on the substrate; orthographic projections of the top electrode, the piezoelectric layer, the bottom electrode and the acoustic reflection structure on the substrate have an overlapping region; the overlapping region is an asymmetric region; the contour of the overlapping region is formed by connecting a first curve and a second curve end to end; and the first curve and the second curve are different in shape. Thus, when transverse sound waves are propagated in the overlapping region, because the contour of the overlapping region is composed of two curves, the transverse sound waves can be reflected at different angles after being reflected by the curve edges, so that the regularity of the propagation path of the transverse sound waves is destroyed, an irregular state is presented, excitation of transverse standing waves can be effectively weakened, the transverse pseudo mode of the bulk acoustic wave resonator is suppressed, and the Q value of the device is improved.

Description

technical field [0001] The present application relates to the technical field of filters, in particular, to a bulk acoustic wave resonator and a bulk acoustic wave filter. Background technique [0002] With the rapid development of wireless communication, wireless signals are becoming more and more crowded, and new requirements such as integration, miniaturization, low power consumption, high performance, and low cost are put forward for filters working in the radio frequency band. Traditional surface acoustic wave filters will be increasingly unable to meet such standards due to limitations in frequency and power. Film Bulk Acoustic Resonator (FBAR) has gradually become a hot spot in the research of RF filters due to its characteristics of CMOS process compatibility, high quality factor (Q value), low loss, low temperature coefficient, and high power carrying capacity. [0003] The Q value is an important index to measure the performance of the resonator. The reduction of ...

AI Technical Summary

Problems solved by technology

[0004] In the existing BAW resonator structure, the effective working area is usually designed as a polygon or an irregular shape combining straight sides and curved sides, but since the setting of straight sides will increase the probability of excitation of the transverse standing wave of the BAW resonator, thereby affecting device performance

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