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how to model random " conductivity" variation?

Posted Mar 16, 2012, 1:50 a.m. EDT Materials, Mesh Version 4.2, Version 4.2a 7 Replies

Ted Zhang
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Hi,
I am doing an AC/DC study of spreading resistance. for example, I have a fixed shape block of Semiconductor (poly-Si) which is made of small grains(polycrystalline ). these small grains has slight variation on the conductivity, let us say their value falls within +/- 0.1% of the standard value. now I want to simulate this situation in my model. I think Mesing will take care of cut the semiconductor block into small pieces, and I assume I should use a random function to add to the materials' conductivity for simulation of the variation, but I don't know the correct procedure to set it up. could you guys give me some suggestions?

regards,
7 Replies Last Post Dec 3, 2012, 1:36 a.m. EST
Ted Zhang
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Posted: 1 decade ago Mar 21, 2012, 2:49 a.m. EDT
hi,
can anyone shine some light on this? or do I have to use Matlab to do this?

regards,
hi, can anyone shine some light on this? or do I have to use Matlab to do this? regards,
Ralf Tschiesche
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Posted: 1 decade ago Mar 21, 2012, 10:58 a.m. EDT
Hi!

Please find attached a very simple example for variation with random function for 4.2a.

Ralf
Hi! Please find attached a very simple example for variation with random function for 4.2a. Ralf
Ted Zhang
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Posted: 1 decade ago Mar 21, 2012, 1:48 p.m. EDT
Hi, Ralf,
thanks, but I did not see the attachment.

regards,
ted
Hi, Ralf, thanks, but I did not see the attachment. regards, ted
Ted Zhang
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Posted: 1 decade ago Mar 22, 2012, 12:48 a.m. EDT
Ralf,
thanks , I got the attached file. Probably internet browser's problem, Chrome vs. Firefox. now I built my own random variation model as attached. but I have another concern: once I mesh the stricture and COMSOL assign the random conductivity variation to each element, I want to keep this meshing fixed (with the corresponding conductivity). then later I could retreat the structure with the same spatial elements, and the same conductivity variation to each element, in order to study the impact of the variation on my measurement cross the wafer. I know you could export the meshing, later import it back. but I wonder when you export the mesh, will COMSOL export the corresponding material properties too? like the conductivity in this case.


my model is too big to attach (it is not your browser's fault ^-^)

thanks,
ted
Ralf, thanks , I got the attached file. Probably internet browser's problem, Chrome vs. Firefox. now I built my own random variation model as attached. but I have another concern: once I mesh the stricture and COMSOL assign the random conductivity variation to each element, I want to keep this meshing fixed (with the corresponding conductivity). then later I could retreat the structure with the same spatial elements, and the same conductivity variation to each element, in order to study the impact of the variation on my measurement cross the wafer. I know you could export the meshing, later import it back. but I wonder when you export the mesh, will COMSOL export the corresponding material properties too? like the conductivity in this case. my model is too big to attach (it is not your browser's fault ^-^) thanks, ted
Ralf Tschiesche
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Posted: 1 decade ago Mar 22, 2012, 5:57 a.m. EDT
Hi!

Maybe you can export sigma to a text file (see export, without header), re-import it as a interpolation (see global definition->interpolation) and define sigma from this function (see material).

Ralf
Hi! Maybe you can export sigma to a text file (see export, without header), re-import it as a interpolation (see global definition->interpolation) and define sigma from this function (see material). Ralf
Ralf Tschiesche
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Posted: 1 decade ago Mar 22, 2012, 5:57 a.m. EDT
Hi!

Maybe you can export sigma to a text file (see export, without header), re-import it as a interpolation (see global definition->interpolation) and define sigma from this function (see material).

Ralf
Hi! Maybe you can export sigma to a text file (see export, without header), re-import it as a interpolation (see global definition->interpolation) and define sigma from this function (see material). Ralf
Ralf Tschiesche
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Posted: 1 decade ago Dec 3, 2012, 1:36 a.m. EST
Hi!

Only for the sake of completeness: attached the models...

Ralf
Hi! Only for the sake of completeness: attached the models... Ralf

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