New-type membrane bulk acoustic wave resonator and preparation method thereof

Abstract

The invention relates to the field of a microelectronic device, and specifically provides a new-type membrane bulk acoustic wave resonator and a preparation method thereof. The membrane bulk acoustic wave resonator comprises a Si substrate, a Si bonding layer bonded on the Si substrate and a monocrystal lithium niobate slice arranged on the Si bonding layer. Cavities are arranged on the upper surface of the Si bonding layer. Lower electrodes correspondingly arranged in the cavities are attached to the lower surface of the monocrystal lithium niobate slice. Upper electrodes are arranged on the upper surface of the monocrystal lithium niobate slice. The upper electrodes and the lower electrodes are arranged correspondingly. According to the resonator provided by the invention, the monocrystal lithium niobate slice is taken as a piezoelectric layer; the lattice orientation of the piezoelectric layer can be conveniently and accurately controlled; the performance such as resonant frequency and an electromechanical coupling coefficient of the resonator can be remarkably improved; moreover, the monocrystal lithium niobate slice is taken as a device support structure; the performance damage resulting from electrode support can be effectively avoided; the performance of the device is further improved; the resonator is simple in structure and good in processing repeatability; and the large-scale line array with good consistency can be obtained.

Description

technical field [0001] The invention relates to the field of microelectronic devices, in particular to a novel film bulk acoustic wave resonator and a preparation method thereof. Background technique [0002] With the rapid development of the communication field, the era of big data has arrived. The low-frequency spectrum is completely occupied, while the technology development of the high-frequency spectrum still needs to be developed; the traditional mature surface acoustic wave resonator is difficult to break through the frequency above 2Ghz due to the limitation of the manufacturing process; the new generation of thin film bulk acoustic wave resonator is very difficult. It solves the technical difficulties in this aspect well, and can easily realize the resonator applied in the high frequency band. At present, thin film bulk acoustic resonators are mainly divided into support structure and cavity structure; in the support structure, the silicon substrate has a great inf...

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Problems solved by technology

At present, thin film bulk acoustic resonators are mainly divided into support type structure and cavity type structure; the silicon substrate in the support type structure has a great influence on the device structure, resulting in lower fundamental frequency resonance frequency and Q value; and cavity type structure Electrodes are used for support and piezoelectric materials are grown on the electrodes. During the growth process, it is difficult for the piezoelectric materials to obtain a suitable lattice orientation, resulting in multiple harmonics in the device. Moreover, the thickness of the electrodes affects the performance of the thin film bulk acoustic resonator. The damage, such as reduction of resonance frequency and electromechanical coupling coefficient

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