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Thin film Hardness by PDNISP

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Ranna posted on Tue, Jul 24 2012 2:28 PM

Hello

I have some problem with measuring the hardness value of the thin film by using PDNISP tip on AFM.

I am using the Nanoscope Analysis, but just hte Young's modulus is calculated not the hardness.

Could some one with more experience on measuring the hardness and young's moduls help me on this matter?

 

Regards

Ranna

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Answered (Verified) Verified Answer

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Bruker Employee

Hi Ranna,

With AFM, hardness is usually evaluated based on the residual indentation left after the indent.  It is usually defined as Hardness=Maximum load/projected area of the pit left by the indent.  The Maximum load is just your ramp mode trigger (assuming you are using relative triggering and you have calibrated deflection sensitivity and spring constant).  The projected area of the indent can be analyzed using the "Width" or "Particle Analysis" functions (click on the blue '?' icon for help).

--Bede


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Verified by Ranna

To get the load-displacement curve, you need to take the usual AFM force curve and compensate for the cantilever bending.  We call this a force-separation plot.  Separation is the negative of deformation up to a constant.  You can find a display mode in the force curve view that allows you to look at the curves this way.  If you want to make it look like indentation load displacement curves, you will have to export the curves and calculate the displacement axis yourself.  Displacement in nm=Z piezo extension in nm - Cantilever deflection in nm - Constant that sets the zero deformation point.

--Bede

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Verified by Ranna

Hi Ranna,

Yes, it is possible that the tip could be contaminated and that the contamination is dominating the measurement.  There are several methods for cleaning the probe.  Most involve indenting a soft material such as gold or rubber with a high force.

--Bede

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Top 10 Contributor
280 Posts
Points 6,219
Bruker Employee

Hi Ranna,

With AFM, hardness is usually evaluated based on the residual indentation left after the indent.  It is usually defined as Hardness=Maximum load/projected area of the pit left by the indent.  The Maximum load is just your ramp mode trigger (assuming you are using relative triggering and you have calibrated deflection sensitivity and spring constant).  The projected area of the indent can be analyzed using the "Width" or "Particle Analysis" functions (click on the blue '?' icon for help).

--Bede


Top 150 Contributor
6 Posts
Points 70
Ranna replied on Wed, Jul 25 2012 1:10 PM

Idea

Thanks a lot Bede... it was a helpful tip... and maybe simple, but I am new in AFM!! Smile

but I was wondering if with this data that I have now, can I plot the typical nanoindentation graph which usallu can be extracted by Nanoindentater test?... I have extracted the ASCII file of the indentation, but there is no connection between the extend data and retract data when I replot it in excel...

Ranna

  • | Post Points: 12
Top 10 Contributor
280 Posts
Points 6,219
Bruker Employee
Verified by Ranna

To get the load-displacement curve, you need to take the usual AFM force curve and compensate for the cantilever bending.  We call this a force-separation plot.  Separation is the negative of deformation up to a constant.  You can find a display mode in the force curve view that allows you to look at the curves this way.  If you want to make it look like indentation load displacement curves, you will have to export the curves and calculate the displacement axis yourself.  Displacement in nm=Z piezo extension in nm - Cantilever deflection in nm - Constant that sets the zero deformation point.

--Bede

  • | Post Points: 13
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Ranna replied on Mon, Jul 30 2012 11:49 AM

Thanks Bede, it was a short but sharp answer which I was waiting from the company for weeks...

Good luck in your research

Ranna

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Ranna replied on Wed, Aug 8 2012 1:47 PM

I have reach to another question?

after few days of nanoindentation, suddenly there is no more indentation on the surface after indenting. 

the substrate that I am using is silicon. With different forces applied there are different force calibration plot but no indentation at all.

in some samples there might be polymeric parts due to modifications, is it possible that diamond tip contaminated?

 

appreciate your help in advance 

Ranna

 

  • | Post Points: 12
Top 10 Contributor
280 Posts
Points 6,219
Bruker Employee
Verified by Ranna

Hi Ranna,

Yes, it is possible that the tip could be contaminated and that the contamination is dominating the measurement.  There are several methods for cleaning the probe.  Most involve indenting a soft material such as gold or rubber with a high force.

--Bede

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