Film bulk acoustic resonator

By introducing a temperature compensation layer on the piezoelectric layer and fabricating a recessed structure thereon, the process implementation and stability issues of the recessed structure in high-frequency FBAR products were solved, achieving high Q value and temperature stability of the thin-film bulk acoustic resonator, thus meeting the performance requirements of high-frequency communication systems.

WO2026123580A1 Publication Date: 2026-06-18WUHAN MEMSONICS TECH CO LTD
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Patent Information

Authority / Receiving Office
WO · WO
Patent Type
Applications
Current Assignee / Owner
WUHAN MEMSONICS TECH CO LTD
Filing Date
2025-05-13
Publication Date
2026-06-18

AI Technical Summary

⚠Technical Problem

In the existing technology, recessed structures in high-frequency FBAR products have problems with process implementation and structural stability. In particular, when fabricating recessed structures on the upper electrode layer and passivation layer, it is difficult to achieve a stable and effective thickness and shape, which affects the performance of the resonator.

⚗Method used

A temperature compensation layer is introduced on the piezoelectric layer, and the recessed structure is fabricated on the temperature compensation layer. This avoids damage to the recessed structure during the frequency correction process, increases the depth range of the recessed structure, reduces the process difficulty, and reduces the frequency-temperature coefficient of the resonator by selecting the material of the temperature compensation layer.

🎯Benefits of technology

This approach increases the stability and depth range of the recessed structure, reduces the manufacturing difficulty, and improves the Q value and temperature stability of the thin-film bulk acoustic resonator, thus meeting the performance requirements of high-frequency communication systems.

✦ Generated by Eureka AI based on patent content.

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Abstract

The present application relates to the technical field of resonators. Disclosed is a film bulk acoustic resonator. The film bulk acoustic resonator comprises a substrate, and a bottom electrode, a piezoelectric layer and a top electrode which are arranged on the substrate in sequence, wherein a groove is provided in the substrate; an overlapping region of the bottom electrode, the piezoelectric layer and the top electrode in a stacking direction serves as a resonance region; and a temperature compensation layer is provided on the piezoelectric layer, an orthographic projection of the temperature compensation layer on the substrate falls within the range of an orthographic projection of the resonance region on the substrate, and a recessed structure is provided in the temperature compensation layer. In the film bulk acoustic resonator, a temperature compensation layer is introduced onto a piezoelectric layer, and a recessed structure is prepared in the temperature compensation layer, such that damage to the recessed structure caused by a frequency trimming process can be avoided, and a relatively large depth range of the recessed structure can be achieved, thereby reducing the process difficulty, and also decreasing a frequency-temperature coefficient of the resonator.
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