Specific Process Knowledge/Characterization/AFM: Atomic Force Microscopy: Difference between revisions
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|style="background:silver; color:black"| | |style="background:silver; color:black"| | ||
|style="background:LightGrey; color:black"|[[#Height Accuracy|Height (z) accuracy]] | |style="background:LightGrey; color:black"|[[#Height Accuracy|Height (z) accuracy]] | ||
|style="background:WhiteSmoke; color:black"|better than 2% (at 200 nm), typically better | |style="background:WhiteSmoke; color:black"|better than 2% (at 200 nm), typically better than 0.75% | ||
|style="background:WhiteSmoke; color:black"|better than 2% (at 200 nm), typically better | |style="background:WhiteSmoke; color:black"|better than 2% (at 200 nm), typically better than 0.75% | ||
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===Tip status=== | ===Tip status=== | ||
''This section is written by Jesper Pan @DTU Nanolab | ''This section is written by Jesper Pan @DTU Nanolab | ||
When measuring a sample using an AFM, the resulting image is the convolution of the tip shape and sample shape. | When measuring a sample using an AFM, the resulting image is the convolution of the tip shape and sample shape. | ||
As the tip is | As the tip is used, it will become less sharp, thus the resulting image appear blurry. | ||
This effect is especially visible when imaging samples with sharp/edged features, and drastically change roughness parameters like R<sub>max</sub>, R<sub>q</sub> and R<sub>a</sub>. Therefore it is important to be able to identify a worn tip. | This effect is especially visible when imaging samples with sharp/edged features, and drastically change roughness parameters like R<sub>max</sub>, R<sub>q</sub> and R<sub>a</sub>. Therefore it is important to be able to identify a worn tip. | ||
The figure below shows a comparison of the [https://www.budgetsensors.com/sample-for-tip-evaluation-tipcheck | The figure below shows a comparison of the [https://www.budgetsensors.com/sample-for-tip-evaluation-tipcheck TipCheck sample]. | ||
The left image shows a worm tip scanning across a rough surface with sharp edges. Due to tip convolution you practically use the sample to measure the shape of the tip. In this case, the tip is an oval pointing towards the top left, which causes all features to look like that. Furthermore, the worn tip is too big to reach bottom of the trenches between the structures. Which result in a lower measured roughness and Z-range. | The left image shows a worm tip scanning across a rough surface with sharp edges. Due to tip convolution you practically use the sample to measure the shape of the tip. In this case, the tip is an oval pointing towards the top left, which causes all features to look like that. Furthermore, the worn tip is too big to reach bottom of the trenches between the structures. Which result in a lower measured roughness and Z-range. | ||
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| [[File:AFMNewTip.jpg|thumb|left|alt=Image taken using a new probe| AFM image of the tip checker sample taken using a new AFM probe]] | | [[File:AFMNewTip.jpg|thumb|left|alt=Image taken using a new probe| AFM image of the tip checker sample taken using a new AFM probe]] | ||
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! Image Parameters | ! Image Parameters | ||
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* Scan mode: PeakForce Tapping | * Scan mode: PeakForce Tapping | ||
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* Size: 1µm | * Size: 1µm | ||
* Scan Speed: 1Hz | * Scan Speed: 1Hz | ||
* Samples/line: 256 | |||
* | |||
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* Scan mode: PeakForce Tapping | * Scan mode: PeakForce Tapping | ||
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* Size: 1µm | * Size: 1µm | ||
* Scan Speed: 1Hz | * Scan Speed: 1Hz | ||
- | * Samples/line: 256 | ||
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! Roughness information | |||
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* R<sub>q</sub>: 2.49 nm | |||
* R<sub>a</sub>: 1.97 nm | |||
* R<sub>max</sub>: 18.8 nm | |||
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* R<sub>q</sub>: 10.5 nm | * R<sub>q</sub>: 10.5 nm | ||
* R<sub>a</sub>: 8.45 nm | * R<sub>a</sub>: 8.45 nm | ||
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| Same sample taken with a new probe. The triangular structures are pointing in different directions. Higher measured roughness as the sharper tip can map the trenches between the triangles. | | Same sample taken with a new probe. The triangular structures are pointing in different directions. Higher measured roughness as the sharper tip can map the trenches between the triangles. | ||
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