The First 3-D-Printed z-Axis Accelerometers With Differential Capacitive Sensing

In this paper, additive manufacturing and wet metallization process are combined to fabricate three prototypes of differential electro-mechanical z-axis accelerometers. The smart combination of existing fabrication processes makes the proposed fabrication flow unique in the sensors field. The mechanical design of the three proposed devices exploits the threedimensionality of the 3-D-printing technique and the electrostatic differential readout is allowed thanks to the wet-metallization process of the printed structure. Experimental measurements show a very good agreement with theoretical predictions thus proving a good reliability of the proposed design flow and fabrication process. With their relative small footprints (minimum dimension in the order of hundreds of μm), good performances (sensitivity >12 fF/g, sub % linearity error up to 11 g of full scale and theoretical noise estimation of few tens of ng/√Hz) and high customizability, they represent an important step toward novel application fields of inertial sensors.