Preparation method of single crystal film bulk acoustic wave resonator with annular grooves and strip-shaped protrusions on electrodes

Abstract

The invention discloses a preparation method of a single crystal film bulk acoustic resonator with an electrode provided with an annular groove and strip-shaped protrusions, and the method specifically comprises the following steps: sequentially depositing a stripping layer and a piezoelectric layer on a substrate, depositing a lower electrode on the piezoelectric layer, preparing an annular groove on the lower electrode, and depositing two strip-shaped protrusions and a sacrificial layer wrapping the two strip-shaped protrusions, depositing a protective layer wrapping the sacrificial layer on the piezoelectric layer, and depositing a to-be-bonded layer II wrapping the protective layer on the piezoelectric layer; then, bonding a to-be-bonded layer I and a to-be-bonded layer II on the substrate, removing the stripping layer and the substrate, depositing an upper electrode on the piezoelectric layer, preparing an annular groove on the upper electrode, and depositing two strip-shaped bulges on the upper electrode; finally, forming a through hole in the piezoelectric layer, wherein the bottom of the through hole is opened in the surface of the sacrificial layer, and the sacrificial layer is removed through the through hole to form a cavity. The lower ring groove, the first lower strip-shaped protrusion and the second lower strip-shaped protrusion are arranged on the lower electrode of the resonator, the upper ring groove, the first upper strip-shaped protrusion and the second upper strip-shaped protrusion are arranged on the upper electrode, and the frequency and the Q value of the resonator are improved.

Description

technical field [0001] The invention relates to a thin-film bulk acoustic wave resonator, in particular to a method for preparing a single-crystal thin-film bulk acoustic wave resonator with electrodes with ring grooves and strip-shaped protrusions. Background technique [0002] Compared with polycrystalline films, single crystal piezoelectric films can prepare thin film bulk acoustic resonators with higher frequency and Q value, so researchers are more inclined to apply single crystal piezoelectric films to thin film bulk acoustic resonators for research. However, due to the relatively difficult preparation process of single crystal thin film bulk acoustic resonators, if the conventional structure and shape of the upper electrode are blindly changed, and the upper electrode with a complex structure is used to further increase the frequency and Q value of the thin film bulk acoustic resonator, the preparation process will be brought The current level of technology in our cou...

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Problems solved by technology

However, due to the relatively difficult preparation process of single crystal thin film bulk acoustic resonators, if the conventional structure and shape of the upper electrode are blindly changed, and the upper electrode with a complex structure is used to further increase the frequency and Q value of the thin film bulk acoustic resonator, the preparation process will be brought The current level of technology in our country is also difficult to keep up with the increasingly complex design of the upper electrode structure. The economic benefits brought by this kind of research will be very limited, which is obviously unsustainable.

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