Evaluation of charge drives for scanning probe microscope positioning stages

Due to hysteresis exhibited by piezoelectric actuators, positioning stages in scanning probe microscopes require sensor-based closed-loop control. Although closed-loop control is effective at eliminating non-linearity at scan speeds below 10 Hz, it also severely limits bandwidth and contributes sensor-induced noise. The need for high-gain feedback is reduced or eliminated if the piezoelectric actuators are driven with charge rather than voltage. Charge drives can reduce hysteresis to less than 1% of the scan range. This results in a corresponding increase in bandwidth and reduction of sensor induced noise. In this work we review the design of charge drives and compare them to voltage amplifiers for driving lateral SPM scanners. The first experimental images using charge drive are presented.