An electrostatic field sensor operated by self-excited vibration of MEMS-based self-sensitive piezoelectric microcantilevers

We have developed MEMS-based electrostatic field sensors (MEMS-EFS) composed of probe to detect electrostatic field and self-sensitive piezoelectric microcantilevers. The self-sensitive piezoelectric microcantilevers have Pb(Zr,Ti)O₃ (PZT) thin films for sensor and actuator. The MEMS-EFS were fabricated through sol-gel deposition of PZT thin films and MEMS microfabrication process. An output voltage of the PZT thin films for sensor was found to be proportional to the displacement of the microcantilevers. Self-excited vibration of the microcantilevers has been achieved by amplifying and forwarding the output voltage of the PZT thin films for sensor with a band pass filter circuit. The developed MEMS-EFS can evaluate an electrostatic field of -3 to 3 kV with good linearity.