Improvement of Alternative Non-Raster Scanning Methods for High Speed Atomic Force Microscopy: A Review

The invention of the nanotechnology adds a new branch to investigate and control the physical properties of matters at atomic level. The aim of this technology is to image the characteristics of metals, biological organs, and polymers. Scanning probe microscopy (SPM) opens a new branch to analysis the atomic properties of the matters. Atomic force microscopy (AFM), a branch of SPM, is a versatile tool of nanotechnology to image both conductive and non-conductive matters with high resolution. Commercial AFM uses raster scanning technique to produce image of the matters that is responsible for low scanning speed and image quality. The performances of AFM are hampered due to low bandwidth of the scanning unit and vertical Proportional-Integral (PI) controller and may damage the surface of the samples. Different non-raster scanning techniques such as sinusoidal, rotational, spiral, cycloid, and lissajous scanning have been proposed to overcome the limitations of raster scanning method by providing high scanning speed, image quality, and resolution. This paper presents a survey of raster and non-raster scanning methods for high speed AFM and provides a compression between them in term of scanning speed, bandwidth and highest achievable scanning frequency. The control techniques applied to the AFM for improving raster, sinusoidal, spiral, cycloid, and lissajous scanning methods are studied in this paper to find most optimum scanning technique for AFM.