A High Dynamic Range AFM Probe with Collocated Piezoelectric Transducer Pairs

A new class of piezoelectric cantilevers is presented for dynamic mode atomic force microscopy (AFM). Twin isolated, two-layer piezoelectric stack transducers are microfabricated side-by-side on a Si AFM probe. The top transducer on one pair is used to actuate the probe into oscillation. The remaining pair of transducers are used to differentially sense the cantilever deflection. This probe exhibits a negligible electrical feedthrough, which is a key issue with piezoelectric cantilevers. The piezoelectric sensors capture the full dynamics of the resonating cantilever at the first mode. Obtaining a high dynamic range with this differential sensing pair at this mode makes the cantilever a suitable candidate for high-resolution dynamic AFM imaging. It is worth mentioning that stacking the two layer pair of transducers enables optimal use of available surface area on small microcantilevers.