Atomic Force Microscope Probe with Metrology, for Subatomic Measuring Machine (SAMM)

Together with University of North Carolina at Charlotte, we have built a magnetically-suspended stage designed to achieve 0.1-nm resolution, 1-nm repeatability, and 10-nm accuracy over a macroscopic range of 25 mm in X,Y and 100 microns in Z. To complete the project, we are currently developing an atomic force microscope head to allow accurate characterization of the performance of the LORS stage. This probe senses tip-sample separation using a miniature piezoelectric quartz tuning fork. When driven with an AC voltage at its resonant frequency and with a sharp tip mounted to one end, this sensor can resolve topographic features on the atomic scale. Development of integrated metrology with the inherent accuracy of the system remains one of the key design challenges. Scanned probe microscopy typically relies on open-loop control of PZT actuators, which may introduce errors due to hysteresis. Our design will incorporate closed-loop positioning of a PZT tube, thereby improving the probe's accuracy.