Easy-to-integrate FBAR filter

Abstract

The invention provides an easy-to-integrate FBAR filter. The easy-to-integrate FBAR filter comprises a plurality of supporting legs of Bragg reflection layer structures, a first resonator and a second resonator, the first resonator and the second resonator share a plurality of supporting legs with Bragg reflection layer structures; the first resonator is formed by sequentially depositing a mass load, a first upper electrode, a first piezoelectric layer and a first lower electrode; and the second resonator is formed by depositing a second upper electrode, a second piezoelectric layer and a second lower electrode in sequence. The FBAR resonators are connected through the supporting legs to form the filter, and the resonators can form a filter passband by applying mass load frequency modulation on the upper portion of the upper electrode. The FBAR resonators are connected through the supporting legs of the Bragg reflection layer interphase structure distributed transversely, the mechanical quality factor of the FBAR resonators can be improved, the resonator arrangement mode can be diversified and can be a transverse arrangement mode or a longitudinal superposition mode, the integration degree of the filter is improved, and the processing cost is reduced.

Description

technical field [0001] The invention belongs to the technical field of filters, in particular to an easily integrated FBAR filter. Background technique [0002] With the development of modern wireless communication technology towards high frequency and high speed, higher requirements are put forward for front-end filters commonly used in radio frequency communication. While the operating frequency continues to increase, there are higher requirements for device volume, performance, stability, and integration. There are currently two main implementations of filters in radio frequency systems: SAW (Surface Acoustic Wave) filters and BAW (Bulk Acoustic Wave) filters. Compared with surface acoustic wave filters, bulk acoustic wave filters have the advantages of high operating frequency and power capacity. Among them, FBAR (film bulk acoustic resonator) filters have high frequency, low loss, low temperature drift characteristics, and steep filter skirts. Edge and extremely high ...

AI Technical Summary

Problems solved by technology

At the edge of the FBAR structure, the supporting feet of the Bragg reflective layer structure with lateral distribution can be improved, which can improve the mechanical quality factor of the FBAR resonator and improve the performance of the resonator itself. In addition, the construction of traditional FBAR filters often requires additional peripherals outside the FBAR resonator. The support frame enables the integration of multiple resonators, but this traditional connection method often limits the integration of FBAR filters, and the support feet of the FBAR resonators are connected by laterally distributed Bragg reflectors. Diversified distribution methods, which can be arranged horizontally or vertically, which can improve the filter filling factor, improve the integration of the filter, and reduce the processing cost

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