Design of Hybrid Piezoelectric/Piezoresistive Cantilevers for Dynamic-mode Atomic Force Microscopy

摘要

Atomic force microscope cantilevers with integrated actuation and sensing on the chip level provide several distinct advantages over conventional cantilever instrumentation. These include clean frequency responses, the possibility of down-scaling and parallelization to cantilever arrays as well as the absence of optical interferences. However, the two major difficulties with integrated transduction methods are a complicated fabrication process, often involving a number of fabrication steps, and a high amount of feedthrough from actuation to sensing electrodes. This work proposes two hybrid cantilever designs with piezoelectric actuators and piezoresistive sensors to reduce the actuator to sensor feedthrough. The designs can be realized using a commercial microelectromechanical systems fabrication process and only require a simple five-mask patterning and etching process. Finite element analysis results are presented to obtain modal responses, actuator gain and sensor sensitivities of the cantilever designs.