Fast imaging method combining cantilever and feedback signals in contact-mode atomic force microscopy

A fast imaging method in a contact-mode atomic force microscope (AFM) is ex amined for its principle and performance. where the image is acquired by co mbining a cantilever signal and a feedback signal applied to a piezotube. T he frequency component of the feedback signal is restricted in the lower fr equency region to keep the linear relationship between the feedback signal and the displacement of the piezotube. It is shown that the image is basica lly independent of the feedback details since a wide detection bandwidth is certified by the cantilever response much faster than by the feedback resp onse, allowing a fast scanning. The fast scanning, however, enhances the di stortion in the transient region where surface height changes abruptly. Thi s influence can be reduced by choosing the scan line direction for the data acquisition. The combination procedure also reduces the low-frequency nois e in the feedback signal. A 512 x 512-pixel image was obtained in 90 s with out sacrificing the resolution.