Four Point Probe Theory

The Van der Pauw Method is a method used to measure the resistance of materials. It is named after the Dutch physicist Johannes van der Pauw. It is a two-point probe measurement technique, in which a current is passed through the material and the voltage between two points is measured.
  • #1

ScieneShines

2
0
Dear Ladys and Gentlemans,

I want to measure the sheet resistance R_square on a printed product.
My measuring equipment consists a SMU to supply and measure and a four point Probe by Jandel.
As output size I get the electrical resistance R (basically the measured Voltage U divided by the supply current I)
So I have to multiply the geometric factor and a correction factor (correction factor because the width is small)

The derivation for the geometric factor I have found on :
http://www.four-point-probes.com/four-point-probe-...

And the correction factor table is shown here, in my case its on page 54
https://www.iiserkol.ac.in/~ph324/StudyMaterials/G...

Funny but true, I get twice the value than in the reference measurement system (eddy current technology)
So may we can discuss why?
And the bigger Question: why is the resistance calculated in the derivation with U/2I.
In my opinion there is no superposition of currents because they have a different sign.
Thank you in advance,
ScieneShines
 
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  • #2
Well, since you didn't show any of your work, we would have no idea where any error lies.

Now my disclaimer. Not my area of expertise, so take anything I mention merely as a 'second pair of eyes.'

From doing a spot read/scan of the links you supplied, you may have mis-applied the geometry correction. See especially pgs 4 thru 7 of the PDF you referenced. That seems to answer your 'why the factor of two' question and also cover the 'factor of two' error you seem to be getting.

Hopefully the above is at least a place to start!

Cheers,
Tom
p.s. Since this is a schoolwork question, I have requested it be moved to the Homework forum.
 
  • #3
First things first : Thank you for your answer and no this is definitivly not a Schoolwork, Homework or anything else... Did you do those things in school? Respect for that.

I'm 100% sure that i used the correct correction factor.
Symmetry condition are given.
 
  • #4
Welcome to the PF. :smile:
ScieneShines said:
I'm 100% sure that i used the correct correction factor.
I agree with @Tom.G that we need to see your work to be able to help you.
 
  • #5

What is the Four Point Probe Theory?

The Four Point Probe Theory is a method used to measure the resistivity of a material. It involves applying a known current to two outer probes and measuring the voltage between two inner probes. This allows for the calculation of the resistivity of the material.

How does the Four Point Probe Theory work?

The Four Point Probe Theory works by utilizing the concept of Ohm's Law, which states that the current through a conductor is directly proportional to the voltage and inversely proportional to the resistance. By applying a known current and measuring the resulting voltage, the resistance (and therefore the resistivity) of the material can be calculated.

What are the advantages of using the Four Point Probe Theory?

The Four Point Probe Theory has several advantages, including its high accuracy and precision, non-destructive nature, and ability to measure the resistivity of a material regardless of its shape or size. It is also a relatively simple and cost-effective method compared to other techniques.

What are the applications of the Four Point Probe Theory?

The Four Point Probe Theory is commonly used in the semiconductor industry for measuring the resistivity of thin films and wafers. It is also used in materials science research to study the electrical properties of various materials. Additionally, it has applications in the fields of electronics, solar cells, and nanotechnology.

What are the potential sources of error in Four Point Probe measurements?

The accuracy of Four Point Probe measurements can be affected by various factors, such as misalignment of the probes, surface roughness of the material, temperature variations, and contact resistance between the probes and the material. Other sources of error can include improper calibration of the instrument or the presence of impurities in the material being measured.

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