Integration of buried piezoresistive sensors and PZT thin film for dynamic and static position sensing of MEMS actuator

We developed a lead zirconate titanate (PZT) thin film actuator integrated with buried piezoresistors for the dynamic and static deformation sensing of a PZT MEMS actuator. We demonstrated the fabrication of sol-gel deposited PZT thin film devices combined with buried piezoresistors and proved, for the first time, the process compatibility of these materials. Dopant concentration measured by secondary ion mass spectrometry (SIMS) analysis confirms that the piezoresistor was successfully buried into the device. Motion detection of the fabricated MEMS cantilever actuated by the PZT thin film was successful and consistent with optical measurement as well as design values. From these results, we can conclude that our PZT actuator and piezoresistive sensors can be monolithically integrated. The fabrication process developed here can be used for high-stability piezoelectric MEMS actuators with feed-back control of position.