New application for the calibration of scanning probe microscopy piezos

Abstract

Scanners for scanning probe microscopy (SPM) are generally built of piezos, which are used to move the sample with respect to the tip in the x-, y- or z -direction or vice versa. Piezoelectric scanners are usually height calibrated by the manufacturer with laser interferometry, with a calibration grid or with the crystallographic or artificial step of a known height standard. Although the displacement depends on the voltage history of the piezoelectric device, SPM data are collected in one lateral direction to minimize the divergence between the adjusted position and the true position. Here we present the utility of a cheap and easy-to-use fibre-optic displacement sensor. The sensor can be employed in measuring static and dynamic displacement of a z-piezo in order to discuss the influence of the static piezo displacement on the dynamic performance that is needed for SPM purposes. The data collected can be used to characterize the non-linearity and hysteresis for slow and fast z-displacements individually. Slow but large z-displacement refers to the sample tilt; fast but small z-displacement refers to topographic features. Our investigations on interfaces and small surface-deposited particles should derive advantage from the improved accuracy achieved. Copyright © 1999 John Wiley & Sons, Ltd.