Thin film piezoelectric layers for sensing and actuation in microstructures

Silicon micromachined sensors and actuators that incorporate piezoelectric materials are considered. Widespread application has been restricted by the properties of the materials available. The prospects for micromachined piezoelectric devices have improved since it became possible to deposit PbZr_xTi_1-xO₃ layers over large areas with goad uniformity and reproducibility. Considerable progress has been made in developing process technologies for integrating PbZr_xTi_1-xO₃ thin films layers with surface and bulk micromachined structures. As incorporation of these materials in silicon microstructures becomes established it will be possible to consider the integration of bipolar and CMOS electronics with the sensors and actuators. Material and process integration techniques developed to incorporate thin film PbZr_x Ti_1-xO₃ onto bulk micromachined structures are described. The design of a triaxial accelerometer and the processing steps required are outlined