Specific Process Knowledge/Characterization/AFM: Atomic Force Microscopy: Difference between revisions
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==Height Accuracy== | ==Height Accuracy== | ||
Accuracy estimations in AFM measurements are complex and depends on the scale you are interested in. At sub nanometer scale or a few nanometers the height measurement may be affected by the properties of the cantilever tip, your sample material stiffness and the scanning force. These parameters are less important when measuring the 100 nm range and above. At all scales calibration of the Z-piezo is important. Here at DTU Nanolab we calibrate the Z-piezo with a certified sample that is approximately 200 nm in height. This sample height is given with an uncertainty that is calculated based on variation on the calibration sample and measurement uncertainties of the instrument used for certification. The uncertainty on the calibration sample is ≤ 1.5 nm. Following our QC procedure we accept an offset from the certified value of 2%. For a 200 nm sample this is 4 nm. If we use the formula for combined uncertainties the the uncertainty is: 4.3 nm or 2.1% | Accuracy estimations in AFM measurements are complex and depends on the scale you are interested in. At sub nanometer scale or a few nanometers the height measurement may be affected by the properties of the cantilever tip, your sample material stiffness and the scanning force. These parameters are less important when measuring in the 100 nm range and above. At all scales calibration of the Z-piezo is important. Here at DTU Nanolab we calibrate the Z-piezo with a certified sample that is approximately 200 nm in height. This sample height is given with an uncertainty that is calculated based on variation on the calibration sample and measurement uncertainties of the instrument used for certification. The uncertainty on the calibration sample is ≤ 1.5 nm. Following our QC procedure we accept an offset from the certified value of 2%. For a 200 nm sample this is 4 nm. If we use the formula for combined uncertainties the the uncertainty is: 4.3 nm or 2.1% | ||
However when we check the value it is typically less then 1% given a combined uncertainty of: 0.75% | However when we check the value it is typically less then 1% given a combined uncertainty of: 0.75% | ||