A Monolithic Integration Bio-Inspired Three-Dimensional MEMS Vector Hydrophone

Three-dimensional vector hydrophone plays an important role in underwater spatial location. In order to solve the problems of monolithic integration and linearity of previous three-dimensional vector hydrophones, a three-dimensional micro-electro-mechanical system (MEMS) vector hydrophone based on the piezoresistive effect and bio-inspired principle is proposed in this paper. Different from previous three-dimensional vector hydrophone, this three-dimensional MEMS vector hydrophone is monolithically integrated. It has the characteristics of high consistency and batch production. Acoustic pressure gradients in xand y-directions are detected by the cilium, and acoustic pressure gradient in the z direction is detected by the supporting block and beams. Mathematical models of longitudinal stress on the surface of beams and the first three-order natural frequencies of the hydrophone are established. The simulation results prove the accuracy of the mathematical models. Specific structure parameters of hydrophone are determined and then the designed hydrophone is fabricated on a silicon-on-insulator (SOI) wafer. Finally, the sensitivities and directivities of designed hydrophone are tested. The sensitivities of X-channel and Z-channel are -187 dB and -163 dB (0 dB referring to 1 VμPa
^-1
) at 400 Hz, respectively. The test results show that the hydrophone promising in spatial location.