Editing Atomic force microscopy (section)

===Disadvantages===
A disadvantage of AFM compared with the [[scanning electron microscope]] (SEM) is the single scan image size. In one pass, the SEM can image an area on the order of square [[millimeter]]s with a [[depth of field]] on the order of millimeters, whereas the AFM can only image a maximum scanning area of about 150×150 micrometers and a maximum height on the order of 10–20 micrometers. One method of improving the scanned area size for AFM is by using parallel probes in a fashion similar to that of [[Millipede memory|millipede data storage]].

The scanning speed of an AFM is also a limitation. Traditionally, an AFM cannot scan images as fast as an SEM, requiring several minutes for a typical scan, while an SEM is capable of scanning at near real-time, although at relatively low quality. The relatively slow rate of scanning during AFM imaging often leads to thermal drift in the image<ref name="feature2004">{{cite journal|author=R. V. Lapshin|year=2004 |title=Feature-oriented scanning methodology for probe microscopy and nanotechnology |journal=Nanotechnology|volume=15|issue=9|pages=1135–1151|issn=0957-4484|doi=10.1088/0957-4484/15/9/006 |url=http://www.lapshin.fast-page.org/publications.htm#feature2004 |format=PDF|bibcode=2004Nanot..15.1135L |s2cid=250913438 |url-access=subscription}}</ref><ref name="automatic2007">{{cite journal|author=R. V. Lapshin|year=2007 |title=Automatic drift elimination in probe microscope images based on techniques of counter-scanning and topography feature recognition|journal=[[Measurement Science and Technology]]|volume=18|issue=3|pages=907–927 |issn=0957-0233|doi=10.1088/0957-0233/18/3/046|bibcode=2007MeScT..18..907L |s2cid=121988564 |url=http://www.lapshin.fast-page.org/publications.htm#automatic2007|format=PDF|url-access=subscription}}</ref><ref name="scanning1994">{{cite journal|author1=V. Y. Yurov|author2=A. N. Klimov|year=1994|title=Scanning tunneling microscope calibration and reconstruction of real image: Drift and slope elimination |journal=Review of Scientific Instruments|volume=65|issue=5|pages=1551–1557|issn=0034-6748 |doi=10.1063/1.1144890|url-status=dead |url=http://rsi.aip.org/resource/1/rsinak/v65/i5/p1551_s1|archive-url=https://archive.today/20120713061116/http://rsi.aip.org/resource/1/rsinak/v65/i5/p1551_s1|archive-date=2012-07-13|format=PDF |bibcode=1994RScI...65.1551Y|url-access=subscription}}</ref> making the AFM less suited for measuring accurate distances between topographical features on the image. However, several fast-acting designs<ref>{{cite journal|author1=G. Schitter |author2=M. J. Rost |year=2008 |title=Scanning probe microscopy at video-rate |journal=Materials Today |volume=11 |issue=special issue |pages=40–48 |issn=1369-7021 |doi=10.1016/S1369-7021(09)70006-9 |doi-access=free }}</ref><ref>{{cite journal|author1=R. V. Lapshin |author2=O. V. Obyedkov |year=1993|title=Fast-acting piezoactuator and digital feedback loop for scanning tunneling microscopes|journal=Review of Scientific Instruments|volume=64|issue=10|pages=2883–2887|issn=0034-6748|doi=10.1063/1.1144377|url=http://www.lapshin.fast-page.org/publications.htm#fast1993|format=PDF |bibcode=1993RScI...64.2883L|url-access=subscription}}</ref> were suggested to increase microscope scanning productivity including what is being termed videoAFM (reasonable quality images are being obtained with videoAFM at video rate: faster than the average SEM). To eliminate image distortions induced by thermal drift, several methods have been introduced.<ref name="feature2004"/><ref name="automatic2007"/><ref name="scanning1994"/>
[[File:Afm artifact2.png|thumb|Showing an AFM artifact arising from a tip with a high radius of curvature with respect to the feature that is to be visualized]]
[[File:Afm artifact.svg|thumb|AFM artifact, steep sample topography]]

AFM images can also be affected by nonlinearity, [[hysteresis]],<ref name="analytical1995">{{cite journal|author=R. V. Lapshin|year=1995|title=Analytical model for the approximation of hysteresis loop and its application to the scanning tunneling microscope|journal=Review of Scientific Instruments | volume=66|issue=9|pages=4718–4730|issn=0034-6748|doi=10.1063/1.1145314|url=http://www.lapshin.fast-page.org/publications.htm#analytical1995|format=PDF|bibcode = 1995RScI...66.4718L |arxiv=2006.02784|s2cid=121671951}} ([http://www.lapshin.fast-page.org/publications.htm#analytical1995 Russian translation] is available).</ref> and [[Creep (deformation)|creep]] of the piezoelectric material and cross-talk between the ''x'', ''y'', ''z'' axes that may require software enhancement and filtering. Such filtering could "flatten" out real topographical features. However, newer AFMs utilize real-time correction software (for example, [[feature-oriented scanning]]<ref name="fospm2011">{{cite book|author=R. V. Lapshin|year=2011|contribution=Feature-oriented scanning probe microscopy|title=Encyclopedia of Nanoscience and Nanotechnology|editor=H. S. Nalwa|volume=14|pages=105–115|publisher=American Scientific Publishers|location=USA|isbn=978-1-58883-163-7|url=http://www.lapshin.fast-page.org/publications.htm#fospm2011|format=PDF}}</ref><ref name="feature2004"/>) or closed-loop scanners, which practically eliminate these problems. Some AFMs also use separated orthogonal scanners (as opposed to a single tube), which also serve to eliminate part of the cross-talk problems.

As with any other imaging technique, there is the possibility of [[image artifacts]], which could be induced by an unsuitable tip, a poor operating environment, or even by the sample itself, as depicted on the right. These image artifacts are unavoidable; however, their occurrence and effect on results can be reduced through various methods.
Artifacts resulting from a too-coarse tip can be caused for example by inappropriate handling or de facto collisions with the sample by either scanning too fast or having an unreasonably rough surface, causing actual wearing of the tip.

Due to the nature of AFM probes, they cannot normally measure steep walls or overhangs.  Specially made cantilevers and AFMs can be used to modulate the probe sideways as well as up and down (as with dynamic contact and non-contact modes) to measure sidewalls, at the cost of more expensive cantilevers, lower lateral resolution and additional artifacts.