A Practical Guide to SPM
A Practical Guide to SPM
A Practical Guide to SPM
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27<br />
Resolution Issues<br />
The resolution of AFM images can be thought of in terms of lateral (X,Y)<br />
resolution and vertical (Z) resolution.<br />
Lateral Resolution Issues<br />
Tip Shape — As discussed in the previous section on tip shape effects,<br />
the radius of curvature of the end of the tip will determine the highest<br />
lateral resolution obtainable with a specific tip. The sidewall angles of<br />
the tip will also determine its ability <strong>to</strong> probe high-aspect-ratio features.<br />
Pixelization — The Samples/ line parameter in the Realtime menu<br />
determines the number of data points present in the image in the X and<br />
Y scan direction. These data points are commonly called pixels.<br />
Available choices are 512, 256, and 128.<br />
Pixelization affects resolution in that you cannot resolve features smaller<br />
than the pixel size of the image.<br />
For example, if you are acquiring a 50µm x 50µm image with the<br />
Samples/ line parameter set <strong>to</strong> 512, then the pixel size is 98nm<br />
(50µm÷512=0.098µm or 98nm). Thus, you will not be able <strong>to</strong><br />
resolve features smaller than 98nm at a 50µm scan size.<br />
If you want <strong>to</strong> be able <strong>to</strong> see 10nm-sized features, you will need <strong>to</strong><br />
choose a scan size