Frequency-adjustable transverse field excitation film bulk acoustic resonator and preparation method thereof

Abstract

The invention discloses a frequency-adjustable transverse field excitation film bulk acoustic resonator and a preparation method thereof. The frequency-adjustable transverse field excitation film bulkacoustic resonator sequentially comprises electrode aluminum, a piezoelectric substrate lithium tantalate, temperature compensation layer silicon dioxide and substrate silicon from top to bottom, wherein the substrate is provided with a cavity, the cavity is communicated with a release through hole penetrating through the temperature compensation layer and the piezoelectric substrate, and the piezoelectric substrate is made of a single crystal material. Under the condition that the thickness of the piezoelectric substrate is not changed, the center frequency of the resonator changes along with the change of the excitation direction of the electrode pair.

Description

technical field [0001] The invention relates to microelectronic technology, in particular to a frequency-adjustable transverse field-excited film bulk acoustic wave resonator and a preparation method. Background technique [0002] Thin film bulk acoustic resonator has attracted a lot of research attention because of its high Q value, small size, and integration. With the rapid development of mobile communication technology, thin film bulk acoustic resonator has not only been widely used in RF front-ends, It also shows great potential in sensor detection applications, such as biochemical detection, mechanical detection and so on. [0003] There are two main excitation methods for thin film bulk acoustic wave devices. One is to use the thickness field excitation mode. The two electrodes are respectively on both sides of the piezoelectric substrate, and the electric field is along the thickness direction of the substrate; the other is to use the transverse field In the excitat...

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Problems solved by technology

The resonance frequency of the bulk acoustic wave is mainly achieved by changing the thickness of the piezoelectric substrate. The thinner the substrate, the higher the resonance frequency. Therefore, a piezoelectric substrate of one thickness can generally only be used as a bulk acoustic wave device with one resonance frequency. Bulk acoustic wave filters require a variety of piezoelectric substrates with different thicknesses, which greatly increases the difficulty of making the filter

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