Fabrication of fluid-compatible trilayer cantilevers with integrated piezoelectric actuators

Microcantilevers are popular transducers thanks to their simple design and a high sensitivity. In many applications, the cantilevers need to be actuated, either to induce a controlled deflection or to excite the resonance. This can be achieved with integrated actuators, which are easy to operate and require little instrumentation. In this work, a fluid compatible cantilever with integrated piezoelectric actuation is presented. For a 130 mu m long beam, amplitudes on the order of 100 nm are obtained off-resonance in air and in liquid. The results are compared to electrothermal actuation and show that at high frequencies, piezoelectric actuation can reach higher amplitudes than the thermal drive, which suffers from a frequency roll-off related to limited heating and cooling times. Finally, the piezoelectric cantilevers are used for off-resonance tapping atomic force microscopy. Surface probing rates of 100 kHz are achieved in air.