Advanced Piezoelectric-Positioner Controller for High-Speed Scanning Probe Microscopy

This SBIR Phase I project will investigate the feasibility of an improved control strategy for piezoelectric positioners used in scanned-probe microscopes (SPMs) to increase their speed and reliability for nanocharacterization. Rapid nanocharacterization requires fast motion of the scanned piezo probe with sub-Angstrom vertical resolution and with frequent rapid changes in its axial position. Settling time after a change in the position has been commanded is a serious issue that currently places severe limits on speed and reliability: under present control schemes SPMs cannot be operated anywhere near the resonant frequencies of the piezo element. PIEZOMAX Technologies, Inc. proposes to test the feasibility of an improved control scheme that should allow an order of magnitude increase in scan speed of SPMs by reducing settling time. In the feasibility study the control strategy will be designed, implemented digitally, and tested on a variety of piezoelectric positioners used in SPMs. The effect of noise,passive damping, and detuning of the controller will be investigated and comparisons established with the performance of conventional SPMs. The approach should be applicable to a variety of piezoelectric positioners and thus to a broad range of applications in characterization, inspection, and nanopatterning involving scanned probes.