一种梳齿式CMUTs流体密度传感器及其制备方法

The invention discloses a kind of comb-tooth-type CMUTs fluid density sensors and preparation method thereof, comb-tooth-type ultrasonic sensor includes low monocrystalline substrate, there is silica entablature on the substrate, pillar center etching is formed with cavity, cavity upper surface bonds together to form sealant with SOI piece, the SOI piece silicon substrate of bonded wafer is thinned to comb electrodes thickness by polishing process, SOI piece buried layer of silicon dioxide forms silicon dioxide insulating layer simultaneously, bonded wafer top is etched into comb electrodes structure and sealing entablature by heavy doping and DRIE technique, silicon dioxide layer of protection is formed by secondary bond again, and guarantee that comb electrodes structure is in vacuum domain. Using comb teeth ac electrode and comb teeth DC electrode exciting CMUTs membrane structure, pass through the bending vibration for the membrane structure layer that the radial tension and compression campaign for the comb electrodes generation being arranged symmetrically is formed, therefore alternating current being loaded directly into compared to traditional upper and lower electrode and generating the CMUTs structure of vibration, there is higher quality factor.