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vijay pargaonkar October 9, 2000 07:29

I would like to collect the names of persons who are analysing "Soret Effect".

By analysing I mean,

1) Analysis which will show when the soret effect is significant.

2) Analysis which is carried on a transport phenomenon in which mixture of gases is the fluid.

3) Analysis which will forecast the degree of separation of gases due to this effect.

Thanks in advance,

with regards Pargaonkar Vijay C.

Chuck Leakeas October 10, 2000 10:08


I am studying the Soret effect on a SiH4-H2 chemical system inside a chemical reactor. I am investigating the effect that the Soret effect has on the deposition rate of silicon on a wafer surface for the manufacture of microelectronics. So far I have not found any contribution to the deposition rate at 1333.15 K. I will continue my work and keep you posted if you are interested.


vijay pargaonkar October 10, 2000 10:42

Dear Chuck Leakeas,

That is interesting.

Nice to hear that, you are studing SORET EFFECT. BTW, for silicon epitaxy ie (SiH4 and H2 as career gas) Soret effect is normally negligible. That is what is finding from my numerical experiments. Of course it does depend on the specific reactor you are simulating.

I am very much interested in getting data for this effect specially when it is a gasesous mixture. Hope you will find significance of Soret Effect during your experiments. Looking forward to hear from you on my mail id.

pargaonkar vijay

I. Dotsikas October 13, 2000 09:53

Hi Chuck,

The Sorret Effect is only important when you have large temperature gradients AND when the dimensions of your Spacies vary very much; (like WF6 and H2). In this case you should use the multikomponent thoerie of diffussion, too. Under normal circumstances you donīt have any problems with such effects. This effect may be quite important in LPCVD/CVD or in combustion. To tell the truth I have never seen any other application of these theories in an other subject. By the way, do you have great teperature gradients? It doesn't seen to be the case.

SiH4 Deposition bei 1335K.(!!!) I've never heard of that bevor. Do you have any special application? Do you use any Dopants?



Chuck Leakeas October 13, 2000 16:51

Hello Jiannis,

I am looking at a normally impinging jet onto a wafer surface. The mixture in the incoming jet is 298.15K and the wafer is 1333.15K. The separation distance is 0.08 meters so there is a strong temperature gradient in front of the jet. So far I have not been able to detect a difference in the deposition rate even at 1533.15K. It is very possible that I will show that the Soret effect is negligible over a wide range the temperatures and inlet concentrations for this particular reactor design and operating conditions. Good luck in your research.


vijay pargaonkar October 18, 2000 00:23

Dear chuck,

Your problem under investigation seems interesting. can provide me the geometry and boundary conditions?

I will try it for differnet epitaxies. I agree with Mr Dotsikas. He has raised valid points. (Mr Dotsikas thank you.).

One more thing I send you two mails. Both of them bounced back. Can you please provide me your alternative email id.

with regards pargaonkar vijay

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