Thin-film bulk acoustic resonator

A thin-film bulk acoustic resonator (FBAR or TFBAR) is a device consisting of a piezoelectric material manufactured by thin film methods between two conductive – typically metallic – electrodes and acoustically isolated from the surrounding medium. The operation is based on the piezoelectricity of the piezolayer between the electrodes.

Basic FBAR structure

FBAR devices using piezoelectric films with thicknesses ranging from several micrometres down to tenths of micrometres resonate in the frequency range of 100 MHz to 20 GHz.^[1]^[2] FBAR or TFBAR resonators fall in the category of bulk acoustic resonators (BAW) and piezoelectric resonators and they are used in applications where high frequency, small size and weight is needed.

^ Lakin, K.M.; Wang, J.S. (1981). "Acoustic Bulk Wave Composite Resonators". Applied Physics Letters. 38 (3): 125–127. Bibcode:1981ApPhL..38..125L. doi:10.1063/1.92298.
^ Lakin, K. (2003). "A review of thin-film resonator technology". IEEE Microwave Magazine. 4 (4): 61–67. doi:10.1109/MMW.2003.1266067.

[1] Lakin, K.M.; Wang, J.S. (1981). "Acoustic Bulk Wave Composite Resonators". Applied Physics Letters. 38 (3): 125–127. Bibcode:1981ApPhL..38..125L. doi:10.1063/1.92298.

[2] Lakin, K. (2003). "A review of thin-film resonator technology". IEEE Microwave Magazine. 4 (4): 61–67. doi:10.1109/MMW.2003.1266067.

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