A thin-film bulk acoustic resonator and its manufacturing process

Abstract

A thin film bulk acoustic resonator is disclosed, comprising a bottom electrode layer, a piezoelectric layer and a top electrode layer arranged on the upper part of the substrate where the acoustic wave reflection structure is located, wherein the part of the piezoelectric layer corresponding to the boundary of the acoustic wave reflection structure passes through the retrograde Polarization treatment to form a depolarized portion. Also disclosed is a manufacturing process of a thin film bulk acoustic resonator, comprising making a bottom electrode layer on a substrate on which an acoustic wave reflection structure is formed or to be formed to cover the acoustic wave reflection structure; making a piezoelectric layer on the bottom electrode layer; The part of the layer corresponding to the boundary of the acoustic wave reflection structure is depolarized to form a depolarized part; and the top electrode layer is made on the piezoelectric layer. The thin-film bulk acoustic resonator and its manufacturing process can inhibit the shear wave from taking energy away from the resonant area above the cavity of the resonator, thereby ensuring the mechanical vibration strength of the resonant area, suppressing parasitic oscillation, and improving the Q value of the resonator.

Description

technical field [0001] This application relates to the field of communication devices, and mainly relates to a thin film bulk acoustic wave resonator and its manufacturing process. Background technique [0002] With the increasingly crowded electromagnetic spectrum and the increase of frequency bands and functions of wireless communication equipment, the electromagnetic spectrum used by wireless communication has grown rapidly from 500MHz to above 5GHz. Therefore, there is a demand for RF front-end modules with high performance, low cost, low power consumption, and small size. also growing. The filter is one of the RF front-end modules, which can improve the transmitted and received signals, and is mainly composed of multiple resonators connected through a topology network structure. Fbar (Thin film bulk acoustic resonator) is a bulk acoustic resonator. The filter composed of it has the advantages of small size, strong integration capability, high quality factor Q when work...

AI Technical Summary

Problems solved by technology

[0005] In order to solve the technical problem that the shear wave at the resonant region above the resonator cavity in the prior art is easy to leak from the edge of the resonator and take away energy, it is difficult to suppress parasitic oscillation, and affect the performance of the device, the present invention proposes a thin film bulk acoustic resonator and Its manufacturing process is used to solve the above problems

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