Author Topic: Using Probe for EPMA to automatically acquire thin film intensities  (Read 2118 times)


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    • John Donovan
If you have Probe for EPMA and the STRATAGem thin film processing, you are all set up to acquire and calculate thin film compositions (and thicknesses) on your EPMA instrument. In Oregon we find that we usually obtain totals between 95 and 105% with excellent precision. We've even attempted characterizing 2 to 3 nm oxide thin films on gold substrates with reasonable results! Generally one has to know the substrate composition in advance.  For us it's usually pure Si.

For more details on acquiring and re-processing this films using Probe for EPMA and STRATAGem please see this topic:

But here is a very short tutorial using Probe for EPMA to automate thin film sample acquisitions. First create three sample setups all with the exact sample elements and conditions, but with three different electron beam energies. One might get by with just two electron beam energies or even acquire 4 different beam energies. 

So for example, we usually acquire thin film intensities at 10 keV, 15 keV and 20 keV.  These voltages usually work well for most thin films between 50 and 200 nm in thickness, but for thinner films we've utilized 6 keV, 8 keV and 12 keV or so. For thicker films one can utilize 15 keV, 20 keV and 25 keV, it all depends on the physics details. We usually run a quick K vs. HV model in STRATAGem just to make sure that the intensities as a function of keV look reasonable.

So just create three duplicate samples from the Acquire! window and then from the Analyze! window edit the beam voltages as desired using the Conditions button, then save them to the sample setups list using the Save To Setups button as seen here:

Then from the Automate! window select your thin film samples and click the Mutiple Setups button to assign all three sample setups to the digitized points as seen here:

These "multiple setups" need to be assigned to *both* your standard samples and your unknown samples. Probe for EPMA will then automatically acquire three samples for each position sample at the three electron beam energies. The STRATAGem output is performed from the Output | Save STRATAGem Format menu.

The neat thing is that the acquisition of three electron beam energies for each sample allows the STRATAGem software to simultaneously calculate *both* composition and thickness at the same time.

« Last Edit: July 02, 2019, 12:08:45 PM by Probeman »
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