Solver NEXT SPM. Instruction Manual
106
7.3. Many-Pass AFM Techniques
This chapter assumes the reader is experienced in performing measurements with NT-
MDT instruments using techniques of contact and semicontact atomic force microscopy.
In general many-pass techniques are used in tasks where other than topography data are to
be obtained at that topography unwanted side effects must be eliminated. The line scanning
proceeds as follows. The first pass along the scanning line is performed in a contact or
semicontact mode to collect local topography characteristics. During the second pass,
acquiring of electrical forces (or potentials), magnetic fields, dissipations, capacitance
distributions etc. is performed. To avoid any influence of surface features on data collected
during the second pass, the probe is raised above the surface at a distance dZ and then
moves following the surface topography contour. The distance dZ is defined so that the
clearance between the oscillating probe and the sample would be big enough to avoid the
influence of surface topography on measurement results. However, this distance should not
be too big so that the detection signal is strong enough and the lateral resolution is not lost.
Some techniques needs the third pass to minimize the influence of surface electrical fields
(in addition to the influence of surface topography features).
7.3.1. Magnetic Force Microscopy
7.3.1.1. Brief Description
Magnetic Force Microscopy (MFM) is a technique for imaging of spatial distributions of
magnetic fields on the sample surface. MFM is used to study properties of magnetic data
storage devices, magnetic structure of magnetics with sub-micron resolution, magnetic
fields of busbars etc. For this technique, elimination of the influence of surface topography
features on the image of the magnetic forces distribution is the most critical problem. To
solve this problem, magnetic measurements are performed using the two-pass
measurement scheme.
Scanning proceeds as follows. In the first pass, surface topography of the scan line is
measured in the SemiContact Mode (see Fig. 7-76).
Fig. 7-76. First pass
Surface topography imaging
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