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A Simple Scanning Method Based on a Sinusoidal Waveform for High Speed Atomic Force Microscopy
Y-Y. Wang, X-D. Hu and L-Y. Xu

High speed atomic force microscope (AFM) enables dynamic topography measurement of samples on the nanoscale. As the driving component, the bandwidth of the piezoelectric (PZT) scanner mainly affects the scanning speed and the scanning range. The commonly used triangular waveform contains many higher order Fourier components, easily inducing resonance of the PZT scanner; therefore, the conventional scanning method limits the scanning speed to a small range. In the article, the sinusoidal scanning method combined with the equal displacement correction method is put forward to improve the scanning speed of the AFM. Specifically, the PZT scanner is driven by a sinusoidal waveform in the fast axis and a triangular waveform in the slow axis, allowing the scanner to move at high speeds and large ranges without exciting its mechanical resonance. Moreover, the image transformation induced by the non-linearity of the sinusoidal waveform can be eliminated by the implementation of the equal displacement correction method, leading to a highly accurate lateral positioning for the AFM. Experimental results indicate that high quality images can be generated at a high scanning rate with the new scanning method, compared with the conventional triangular scanning method and the cantilever’s scanning speed can reach 1.5 mm/s.

Keywords: Atomic force microscope (AFM), high speed, sinusoidal waveform, triangular waveform, equal displacement correction

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