Actuation and sensing integration challenges at the microscale: the Gordian Knot of the resonant bioMEMS realm

Sensing platforms (5mm*5mm) containing 5 piezoelectric membranes have been fabricated by standard micromachining techniques starting with a Silicon-On-Insulator wafer. Each membrane (circular, with radius varying from 360 microns to 440 microns) could be individually actuated through a PZT 1-micron thick film and sensed either via the same piezoelectric patch or via two terminal piezoresistances (obtained by boron implantation) placed at high-stress location onto the devices. Specific associated electronics (bandwidth of 2 MHz) have been designed and realized so that multiplexed actuation and sensing of all membranes resonant frequencies can be performed either in open-loop or closed-loop mode.