Film bulk acoustic wave device and preparation method thereof

Abstract

The invention provides a film bulk acoustic wave device and a preparation method thereof. The film bulk acoustic wave device comprises a film body with a cavity, a top electrode layer and a bottom electrode layer; the film body with the cavity comprises a first substrate layer and a piezoelectric film layer, and the cavity penetrates through the first substrate layer; the bottom electrode layer is deposited below the exposed piezoelectric film layer in the cavity, and the top electrode layer is deposited on the piezoelectric film layer and is opposite to the bottom electrode layer. Because the bulk acoustic wave generation area is the area covered by the bottom electrode layer and the top electrode layer, compared with the scheme that the two surfaces of the whole piezoelectric film layer are completely covered by the bottom electrode layer and the top electrode layer in the prior art, the film bulk acoustic wave device provided by the embodiment of the invention can reduce the driving voltage and reduce the energy consumption of an acoustic wave filter.

Description

technical field [0001] The application belongs to the field of semiconductor element preparation, and in particular relates to a thin-film bulk acoustic wave device and a preparation method thereof. Background technique [0002] With the development of science and technology, the transmission speed of big data between global systems is increasing day by day, thin film bulk acoustic wave devices are widely used in more and more areas, such as timing clocks, mobile phone radio frequency modules, etc. Thin-film bulk acoustic wave device is a radio frequency filter, which usually adopts a sandwich structure of electrode-piezoelectric film-electrode. The piezoelectric film has piezoelectricity and will generate pressure when a voltage is applied. The upper and lower electrodes of the piezoelectric film are respectively deposited on the upper and lower electrodes. When a voltage is applied to the piezoelectric film crystal, the crystal will undergo mechanical deformation and conve...

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Problems solved by technology

[0004] In order to solve the problem in the prior art that when a voltage is applied to drive the piezoelectric film to vibrate, it is necessary to apply a large driving voltage to make the piezoelectric film reach a resonant state, resulting in a large energy consumption of the bulk acoustic wave filter

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