Piezoelectric bulk material for the fabrication of membrane actuators using surface electrodes for actuation

Using piezoelectric bulk material for manufacturing membrane actuators offers several advantages. Instead of manufacturing e.g. a silicon membrane and then either depositing a piezoelectric thinfilm actuator or mounting a piezo disc or stack to the silicon membrane, it is possible to use the piezoelectric material itself as membrane. Circular lead zirconate titanate (PZT) discs were adapted to silicon surface micromachining technologies. By depositing interdigitated electrode layouts several actuators were structured on one substrate. Those inderdigitated electrode layouts, when actuated, cause an inhomogeneous electric field distribution and thus cause an inhomogeneous mechanical stress distribution within the PZT-substrate. This forces the PZT to deflect in those actuated areas, without the usually needed passive membrane.