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Topic: Arduino based portable four point probe (Read 131 times) previous topic - next topic

Berloondaidai

Hi, I wan to design an arduino project to measure the resistivity of semiconductor by using four point probe method. Can anyone experienced can lend me a hand to point me how to start and complete this project.  :D Is ok if the result is not as accurate as the pro gear, just like more of concept project. Of course i will use battery to make it portable.

Grumpy_Mike

So first read this:- https://en.wikipedia.org/wiki/Four-terminal_sensing

In my undergraduate project in the 70s i use the Van der Pauw method of four point probes to measure the sheet resistivity of a semiconductor.

My worry here is that you will not have enough sensitivity from the internal A/D to make any meaningful measurements. What I would do is to have a floating constant current generator to apply a current to points 1 & 4 and then connect point 3 to the Arduino ground and point 1 to the Arduino analog input.

However, I seem to remember that you had to reverse the polarity of things to get and average reading and that I did with relays. I would recommend the same approach here.

larryd

What part are you having problems with.
What is your background in hardware/software?
Welcome.

Show us a good schematic of your circuit. 
Show us a good image of your wiring.

Always show us your 'current' compete sketch.
Use CTRL T to format the sketch.
Please use code tags.
Use the </> icon in the posting menu.   
[code] Paste sketch here. [/code].

.
No technical PMs.
The last thing you did is where you should start looking.

TomGeorge

Hi,
What do you mean by "the resistivity of semiconductor"?
What range of resistance are you going to be measuring?
How much current can you pass through the semiconductor?

Thanks..  Tom... :)
Everything runs on smoke, let the smoke out, it stops running....

Berloondaidai

Hi TomGeorge,

I mean i will design an arduino based system, and it will work like four point probe to measure the sheet resistance and resistivity of wafer (for exp: silicon). I am new to this so i would like to know any ideas, suggestions and guidance if anyone have experience on this  :D :)

So far i am thinking how to design the 4 probe tip interface to wafer. The current would be around 10mA.

Thank you. Sorry for late reply.

Grumpy_Mike

Quote
So far i am thinking how to design the 4 probe tip interface to wafer.
You want what are called pogo pins, these are spring loaded pins, so that you can push them down a bit without bending them. They have a variety of ends, I think you will want the simple pointed ones. They are mainly used for in circuit testing in production PCBs.


Berloondaidai

Hi Grumpy,

Received your information with thans :) I have PM your inbox :D
thank for your help :)

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