AFM Microcantilever with On-chip Electrothermal and Piezoelectric Transducers: Z-axis Control and Standalone Operation

The Atomic Force microscope (AFM) has limited throughput, which is a major obstacle to its widespread industrial application. This is due to the conventional imaging technique where a single AFM probe interacts with each point on a sample sequentially. In this paper, we propose a solution to this problem by introducing an array of three active microcantilevers that can operate in parallel. Although all three microcantilevers can be used for imaging, in this work, we only report imaging with the central microcantilever, while the other two are held at a fixed height above the sample. Each microcantilever has on-chip piezoelectric and electrothermal actuators that provide high-frequency and large-range Z-motion to the tip, respectively. The deflection of the tip during imaging is measured by an on-chip differential piezoelectric sensor, and the topography of the sample is determined by controlling the deflection. We microfabricated the array of microcantilevers and integrated them with an in-house developed AFM set-up to image several calibration gratings. This work lays the foundation for the parallel operation of multiple AFM probes, which can significantly improve the throughput of AFM in industrial applications.