Research On Key Process Of MEMS Piezoresistive Structure For Flexible Vector Hydrophone

As the core component of underwater underwater detectors,hydrophones determine the accuracy of underwater sound detection.The hydrophone prepared by MEMS technology has the characteristics of small volume and mass production.However,the current reports are generally rigid hydrophones,which cannot achieve curved surface fit with underwater robots.Therefore,this paper proposes a MEMS flexible vector hydrophone,which integrates silicon nanofilms pressure-sensitive units and metal leads with polyimide flexible structures by means of transfer printing.Under the condition of ensuring the working bandwidth,the hydrophone is realized.The curved surface of the hydrophone is attached,which improves the sensitivity of underwater sound detection and reduces the structural size of the hydrophone.Starting from the research background of vector hydrophone,this paper introduces the research status of hydrophone at home and abroad and the research significance of flexible vector hydrophone.Based on the ciliary rigid silicon-based hydrophone,the working principle is analyzed,the generation mechanism of giant piezoresistive effect and the heterogeneous integration method of silicon nanofilms are studied.A MEMS flexible vector hydrophone is fabricated by hetero-integration of lead and flexible polyimide structure.Comparing rigid hydrophones,the advantages of flexible hydrophones are expounded.Through finite element analysis,the structural parameters are determined,and the statics and modal simulations are carried out.It is verified that the flexible vector hydrophone can improve its sensitivity and reduce the structure size while meeting the working bandwidth requirements.The process flow for MEMS flexible vector hydrophone was designed and fabricated.The silicon nanofilms varistor and metal lead were completely transferred to the flexible polyimide structure,realizing heterogeneous integration.The test proves that the silicon nano-film varistor has piezoresistive resistance and pressure-sensitive characteristics,which can meet the needs of flexible hydrophone piezoresistive detection.