Three-axis MEMS DC magnetic sensor using magnetic force interaction with the piezoelectric effect

Abstract

In this paper, we report a novel three-axis MEMS DC magnetic sensor using magnetic force interaction and piezoelectric effect. The sensor includes a back-side-etched silicon diaphragm, a sol-gel PZT thin film with electrodes, and two patterned electroplated Ni thick films. Each patterned Ni film has specific magnetization direction, defined as specific sensing area. As a DC magnetic fields is applied to the sensor, impulse magnetic force and torque are induced to deflect and twist specific Ni films, respectively. Through the mechanical coupling between the Ni films and the PZT film, the deflection and bending are transmitted to the PZT film to produce piezoelectric peak voltages. Experimental results show that, by analysing full duration and half maximum of voltage outputs produced in two sensing areas, the sensor is able to sense three-axial DC magnetic fields.