Piezoelectric MEMS stress sensor with thin lead zirconate titanate (PZT) layer

In this study results from fabrication and testing of MEMS stress sensor with piezoelectric sensitive layer of lead zirconate titanate (PZT) are presented. PZT layers are deposited by RF-sputtering in vacuum. The dependence of the voltage, generated by the structure, on the applied stress is investigated for two different electrode configurations - sandwich type and lateral type, with aluminum electrodes. The obtained results show high piezoelectric coefficient of 186 pC for thickness of PZT-layer of 180 nm. The maximal generated voltage is 35 mV for lateral structure in the stress range of 0-300 mgr. The sandwich structure is sensitive above 1,1 gr and the maximal voltage is 200 mV.