Design and Fabrication of An Ultrasonic Microdevice for Microparticles Separation

In this paper a new microdevice for on-chip separation of microparticles is presented, in which a micromachined silicon nitride membrane structure is bonded with a glass substrate and then PZT plates are bonded to the silicon and glass substrates to excite the microdevice into vibration. Due to the energy coupling, silicon nitride membranes are excited into vibration as well, generating an ultrasonic standing wave field below the membranes, for which we can use it to separate microparticles within the fluids. In the paper, we start from the radiation force analysis and then design and fabricate the practical microdevice, and use finite element method in ANSYS to analyze its separation performance.