Probe Selection and Handling

Probes, whether sharpened wires used for STM or etched silicon for AFM, are the critical component of a Scanning Probe Microscope.

AFM probes are generally made from silicon (Si) or silicon nitride (SiN). In the interest of clarity, certain nomenclature is preferred. An AFM probe (shown in figure 1, below) is comprised of a tip affixed to a cantilever mounted on a substrate, which is inserted in a probe holder. Colloquially, however, you may find that even experts frequently use the term 'tip' when referring to the probe.

Figure 1: A schematic of an AFM Probe, with components labeled. Note that the illustration is not drawn to scale. Also, probes will differ in the number and type of cantilevers attached.

The AFM Probe Holder is colloquially and most commonly referred to as the cantilever holder. It holds the probe in place on the SPM.

Probes for Scanning Tunneling Microscopy (STM) are constructed of platinum iridium (PtIr) or tungsten wire, and as such do not have a solid substrate support. They require a special STM Cartridge for mounting on the SPM.

All SPM probes require special handling. The Dimension Icon is supplied with etched Si and SiN probes for TappingMode AFM and Contact AFM. They should be inspected under an optical microscope when used for the first time to gain a better understanding of how the probes and substrates are connected and separated. Special probes are designed for use with the Dimension FastScan SPM Scanner. 

In order to obtain the best possible data using your Dimension Icon, you will need to become familiar with the contents of this Guide, including:

• Probe Selection—certain probes are optimized for various samples or imaging modes. Choose the correct tool for your application.
• Probe Handling—cantilever probes are very fragile. Often, they must be carefully separated from a production wafer before they can be used.
• Probe Tip Geometry —tip geometry can sometimes influence image data. Understanding the geometry of a probe tip can help you to minimize this effect and to interpret your data correctly.

For applications in fluid or STM applications, see Probes and Accessories for Fluid Operation and Probes and Accessories for STM Imaging , respectively.

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